HomeMy WebLinkAbout2026-05-12; City Council; Resolution 2026-092Exhibit 1 RESOLUTION NO. 2026-092 .
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF CARLSBAD,
CALIFORNIA, ESTABLISHING SEWER BENEFIT AREA N AND A
CORRESPONDING SEWER CAPACITY FEE IN ACCORDANCE WITH THE 2026
ENGINEER’S REPORT
WHEREAS, in January 1991, the City Council of the City of Carlsbad, initially established sewer
benefit area boundaries and fees for the purpose of collecting revenue to reimburse developers for
constructing public sewer conveyance system improvements serving all property within each benefit
area or to provide funds for the City of Carlsbad to construct the improvements, if necessary, by
Resolution No. 91-21; and
WHEREAS, on May 13, 2025, the City Council adopted Ordinance No. CS-491, amending
Carlsbad Municipal Code Section 13.10.080 to remove the fee amounts from the Municipal Code, state
that sewer benefit area fees shall be adjusted annually by the annual change to the Engineering News-
Record Construction Cost Index, Los Angeles Region and allow sewer benefit area fees and areas to be
changed by resolution in accordance with an associated engineering report instead of by ordinance;
and
WHEREAS, the study entitled, “Engineer’s Report for Sewer Benefit Area N,” dated April 2026,
attached as Attachment A, identifies the sewer facilities that are of proportional benefit to new
development, including redevelopment, calculates a sewer capacity charge for the sewer benefit area,
and includes evidence that the sewer capacity charge does not exceed the city’s reasonable costs of
providing sewer capacity related to new development; and
WHEREAS, the 2026 Engineer’s Report includes the following:
1)A map of Sewer Benefit Area N showing the benefit area boundary
2)A description of the proposed public sewer improvements to include
a) Upgrading up to 1.98 miles of sewer gravity mains with larger diameter pipe and
b)Increasing the capacity of the Home Plant Lift Station wet well
3)An estimate of the probable cost for said improvements in the amount of $30,754,478,
including engineering design, environmental studies, construction contract, contingency,
construction management and inspection, materials testing and public outreach
4)The method and apportionment of costs upon each equivalent dwelling unit for the cost of
sewer facilities related to new development; and
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WHEREAS, staff recommend that the City Council establish Sewer Benefit Area N and its
corresponding capacity fee in accordance with the findings of the 2026 Engineer’s Report; and
WHEREAS, the fee as proposed does not exceed the reasonable costs of constructing the
improvements, and the fees are not levied for general revenue purposes; and
WHEREAS, the fee has an essential nexus to the city’s interest of providing sewer facilities
necessary to serve new development, and the fee is roughly proportionate to the city’s costs of
providing those facilities; and
WHEREAS, the fee is necessary to comply with the Statewide Sanitary Sewer Systems General
Order, Order No. 2022-0103-DWQ, which requires the prevention of sewer spills, which may threaten
public health, beneficial uses of State and federal waters, and the environment and further requires
proactive management of the sanitary sewer system to eliminate spill causes, including the provision
of sufficient capacity to account for population increase and/or new connections from industrial,
commercial and other system users; and
WHEREAS, the City Council has determined it necessary, desirable, and in the public interest to
establish SBA N and its corresponding capacity fee in accordance with the 2026 Engineer’s Report; and
WHEREAS, in accordance with Carlsbad Municipal Code Section 13.10.080 and City Council
Resolution No. 91-21, the City of Carlsbad shall use the Sewer Benefit Area N fee revenue to fund sewer
capacity improvements in accordance with the findings of the 2026 Engineer’s Report; and
WHEREAS, the fee complies with Article XIII C, Section 1 of the California Constitution because
it is a charge imposed as a condition of property development that is reasonably related to the costs of
providing public facilities related to that development; and
WHEREAS, a fund would need to be established and maintained to collect the fees so imposed
and the interest collected therein, and be authorized for expenditures on only those projects or other
construction activities set forth in the 2026 Engineer's Report, or revisions thereto as may be approved
and adopted by resolution of the City Council; and
WHEREAS, a report, at least annually, and within six months of the end of the fiscal year, would
be required from the City Manager or designee, determining the beginning and ending balances for the
fiscal year and the Sewer Benefit Area N fees, interest and other income and expenditures on each
public facility; and
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WHEREAS, the fee revenue deposited in the established fund would not be commingled with
any other fees or revenues of the city; and
WHEREAS, the City Council considered the fee at a regularly scheduled public meeting and
provided notice of that meeting and posted the relevant data prior to that meeting pursuant to
Government Code Section 66016; and
WHEREAS, pursuant to Government Code Section 66022, any judicial action challenging the
Sewer Benefit Area N fee must be commenced within 120 days of the City Council’s adoption of the
resolution establishing the fee.
NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Carlsbad, California, as
follows:
1.That the above recitations are true and correct.
2.That the City Council has determined that the proposed action to establish Sewer
Benefit Area N and its fee is not a “project” as defined by California Environmental
Quality Act, or CEQA, Section 21065 and CEQA Guidelines Section 15378(b)(4) and does
not require environmental review under CEQA Guidelines Section 15060(c)(3) because
it is a government fiscal activity and does not involve any commitment to any specific
project which may result in a potentially significant physical impact on the environment.
The activity or project(s) for which the permit, impact or service fee is charged may
require preparation of an environmental document in accordance with CEQA and the
CEQA Guidelines.
3.That the report titled, “Engineer’s Report for Sewer Benefit Area N,” dated April 2026,
on file in the City Clerk’s Office is attached as Attachment A and hereby approved and
adopted by the City Council.
4.That Sewer Benefit Area N will include all properties located within the boundaries
shown in the 2026 Engineer’s Report and Exhibit 2 of the staff report.
5.That the Sewer Benefit Area N fee set forth in Attachment A is hereby adopted, and
once effective, shall be incorporated in the city’s master fee schedule.
6.That the City Manager or designee is directed to establish a fund to collect the revenue
from the fee so imposed and to maintain said fund and the interest collected therein
and to authorize expenditures for only those projects or other construction activities set
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forth in the 2026 Engineer's Report, or revisions thereto as may be approved and
adopted by resolution of the City Council.
7.That the City Manager or designee is further directed to make a report, at least annually,
and within six months of the end of the fiscal year, determining the beginning and
ending balances for the fiscal year and the Sewer Benefit Area N fee revenue, interest
and other income and expenditures on each public facility.
8.That the fees deposited in the fund shall not be commingled with any other fees or
revenue of the City.
9.That the Sewer Benefit Area N is intended to fund sewer capacity improvements
necessary to serve new development consistent with state regulations requiring
proactive sanitary sewer system management to eliminate spill causes and avoid
adverse impacts upon public health or safety.
10. That the Sewer Benefit Area N fee is additional and supplemental to, and not in
substitution of, on-site facility requirements imposed by the city pursuant to zoning,
subdivision, or other city ordinances and regulations, or additional off-site facility
requirements identified through the land development and environmental review
process. The amount of any applicable Sewer Benefit Area N fee to be imposed is to be
calculated at the time of payment, fully paid prior to the issuance of a building permit,
unless deferred in accordance with Government Code Section 66007.
11. That the Sewer Benefit Area N fee shall be adjusted annually effective September 1 in
accordance with Carlsbad Municipal Code Section 13.10.080 by the annual change to
the Engineering News-Record’s Construction Cost Index, Los Angeles region with a base
year index of January 2026 and may be revised by resolution of the City Council in
accordance with an associated engineering report.
12.That this resolution shall take effect immediately and the Sewer Benefit Area N fee shall
become effective 60 days after adoption of this resolution.
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PASSED, APPROVED AND ADOPTED at a Regular Meeting of the City Council of the City
of Carlsbad on the 12th day of May, 2026, by the following vote, to wit:
AYES: Blackburn, Bhat-Patel, Acosta, Burkholder, Shin.
NAYS: None.
ABSTAIN: None.
ABSENT: None.
______________________________________
KEITH BLACKBURN, Mayor
______________________________________
SHERRY FREISINGER, City Clerk
(SEAL)
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CITY OF CARLSBAD
Public Works Branch
Utilities Department
Engineer’s Report
for
Sewer Benefit Area N
April 2026
Signed: April 28, 2026
Attachment A
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TOC-1
Engineer’s Report for Sewer Benefit Area N
Table of Contents
1 Purpose ................................................................................................................................................. 1
2 Introduction .......................................................................................................................................... 1
2.1 Background .................................................................................................................................. 1
2.2 Capacity Charges and Fees .......................................................................................................... 2
2.3 Sewer Benefit Area Program ....................................................................................................... 3
2.4 State Housing Laws ...................................................................................................................... 4
2.4.1 Density Bonus Law .................................................................................................................. 4
2.4.2 Housing Accountability Act ..................................................................................................... 4
2.4.3 Senate Bill 330 ......................................................................................................................... 5
2.4.4 Government Code section 66311.5 ........................................................................................ 5
2.5 Report Organization .................................................................................................................... 5
3 Study Area Description ......................................................................................................................... 6
3.1 Local Facilities Management Zones ............................................................................................. 8
3.2 Density Bonus Yield ..................................................................................................................... 8
4 Summary of Hydraulic Evaluation ......................................................................................................... 9
4.1 Sewer Flow Scenarios .................................................................................................................. 9
4.2 Sewer Improvement Groups ..................................................................................................... 10
4.3 Scoping and Phasing Considerations ......................................................................................... 11
5 Capacity Fee Determination ............................................................................................................... 12
5.1 Methodology ............................................................................................................................. 12
5.2 Cost Estimates ........................................................................................................................... 12
5.3 Recommended Capacity Fee ..................................................................................................... 15
5.4 Accessory Dwelling Units (ADUs) and Junior ADUs ................................................................... 15
6 Future Revisions .................................................................................................................................. 15
APPENDICES
APPENDIX A – Technical Memorandum - Village & Barrio Area Densification Collection System Modeling
APPENDIX B – Sewer Benefit Area N Boundary Maps
APPENDIX C – Cost Summary
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Engineer’s Report for Sewer Benefit Area N 1
1 Purpose
This report provides the basis for establishing a new sewer benefit area, hereinafter referred to
as Sewer Benefit Area N (SBA N), and a proposed sewer capacity charge to fund the city’s sewer
collection system capacity improvements in the city’s northwest neighborhoods of the Village,
the Barrio, North Beach, and a majority portion of Olde Carlsbad generally north of Tamarack
Avenue and west of El Camino Real (see Figure 1).
The report presents the assumptions used
in estimating the future development
density within the evaluation study area
(Study Area) and describes the existing
sewer collection system and the proposed
capacity improvements necessary to
accommodate future growth. The
estimated cost of the proposed capacity
improvements will be charged to each new
development in proportion to the sewer
demand added to the sewer collection
system through the proposed SBA N
capacity charge.
2 Introduction
2.1 Background
Portions of the sewer collection system in the Study Area date back to 1929 when the Carlsbad
Sanitary District constructed a sewer treatment plant near the south shore of the Buena Vista
Lagoon and sewer mains in the downtown area. The Carlsbad Sanitary District provided sewer
collection and treatment services for this area until the City of Carlsbad incorporated in 1952
(City of Carlsbad, 1987 Master Plan of Sewerage).
During the 1960s, Carlsbad’s sewer system “had become overloaded with new developments
occurring since 1952 so a new ’regional‘ plan was developed together with the Vista community
resulting in the construction of shared trunk sewers, pumping stations, and a new regional
treatment plant” (History of City of Carlsbad Water System, Aug 3, 2011). Expansion of the
sewer collection system in the downtown area and areas east of Interstate Highway 5 (I-5)
continued in earnest between the 1950s and early 1970s under the Improvement Act of 1911
through the creation of assessment districts and funded by sewer bonds which were repaid by
the benefiting properties through sewer connection fees, and charges for sewer extension costs
(also known as, “line costs”).
The treatment plant constructed by the Carlsbad Sanitary District, located north and adjacent
to the present-day location of the city’s Home Plant Lift Station (Figure 3), was decommissioned
FIGURE 1. NORTHWEST CARLSBAD NEIGHBORHOODS.
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in 1972. The original Home Plant Lift Station was constructed in 1973 on the original treatment
plant site. Situated at a topographic low point near the Buena Vista Lagoon, the lift station
pumps sewer flow to the shared Vista/Carlsbad Interceptor1 sewer in Jefferson Street near
Laguna Drive for eventual treatment at the Encina Wastewater Treatment Facility. In 1992, the
few remaining facilities from the old treatment plant were demolished and a new sewer lift
station was constructed at the Home Plant site at a slightly higher elevation, south of the
original lift station. The original force main was replaced with a new sewer force main pipeline
extending from the new lift station to the discharge point near Jefferson Street and Laguna
Drive. In 2010, a city capital improvement project upgraded the Home Plant Lift Station and
added a second sewer force main for operational redundancy and capacity.
2.2 Capacity Charges and Fees
Sewer connection fees and sewer capacity charges are often used synonymously but have
distinct definitions and are governed by California Government Code Section 66000 et seq., the
Mitigation Fee Act. Section 66013 defines a capacity charge as “a charge for public facilities in
existence at the time a charge is imposed or charges for new public facilities to be acquired or
constructed in the future that are of proportional benefit to the person or property being
charged, including supply or capacity contracts for rights or entitlements, real property
interests, and entitlements and other rights of the local agency involving capital expense
relating to its use of existing or new public facilities.”
Similarly, a fee is defined as “a fee for the physical facilities necessary to make a water
connection or sewer connection, including, but not limited to, meters, meter boxes, and
pipelines from the structure or project to a water distribution line or sewer main, and the
estimated reasonable cost of labor and materials for installation of those facilities bears a fair
or reasonable relationship to the payor's burdens on, or benefits received from, the water
connection or sewer connection.”
The term “sewer connection fee,” in its original usage by the city in the 1950s, refers to the fee
paid by a new sewer customer to physically connect a private sewer lateral to the city’s sewer
collection system. This connection work, including labor and materials, may have been
performed by city construction staff or a contractor working for the city. Charges for sewer
main extensions, or “line costs” were separate and in addition to sewer connection fees.
The current practice for connecting a private sewer lateral to the city’s sewer main is to require
developers or their contractors to perform the work and bear the cost of labor and materials, in
addition to city plan review, permit and inspection fees. Hence, the city uses the term “fee” in a
broader sense than as defined in the government code.
The city’s present-day usage of the term “sewer connection fees” appears in the city’s Master
Fee Schedule and consists of two components: 1) a citywide capacity fee (listed as General
1 An interceptor sewer is a large diameter sewer that receives wastewater from numerous trunk sewers and
conveys it to a treatment plant.
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Capacity Fee) that applies to all parcels, on an EDU2 basis, within the city’s sewer service area,
and 2) a sewer benefit area fee that applies to parcels, on an EDU basis, within a specific region
or sewer benefit area served by sewer improvements that are funded by the sewer benefit area
“fee.” Both components are charged to the customer upon connection to the city’s sewer
collection system on an equivalent dwelling unit, or EDU, basis and are capacity charges within
the meaning of Government Code Section 66013. These charges are adjusted annually
according to the Engineering News-Record Construction Cost Index, Los Angeles region, to
account for economic inflation. They may also be adjusted in conjunction with special studies
(i.e., master plans or sewer benefit area engineering report updates) to account for growth and
development projections and capacity improvements that are necessary to serve revised EDU
estimates.
In 1990, the citywide capacity fee was revised to include the estimated costs of Phase IV and
Phase V improvements at the Encina Water Pollution Control Facility, the Vista/Carlsbad
Interceptor, and the Home Plant Lift Station. The citywide capacity fee was further revised in
2004 and 2013 following the completion of updates to the city’s sewer master plan. All bonds
previously issued have been repaid and there are no outstanding bond obligations for the
existing sewer collection system in the Study Area.
For consistency with the terminology used in the Sewer Benefit Area program and the city’s
Master Fee Schedule, the proposed capacity charge for SBA N will be referred to as the SBA N
fee hereafter.
2.3 Sewer Benefit Area Program
The Sewer Benefit Area (SBA) program was implemented in 1991 via Resolution No. 91-21 to
levy and collect funds for sewer collection system improvements in future growth areas
identified in the city’s 1986 general plan and located outside of the assessment districts. The
revenue is used to reimburse developers that construct sewer collection system facilities within
the benefit area, or to provide funds for the city to construct the improvements if necessary.
Sewer benefit area fees have funded a total of 38 facilities, such as sewer mains and lift
stations.
The original engineering report titled, “Benefit Area Fees for Conveyance System Improvements
Update to the December 1987 City of Carlsbad Master Plan of Sewerage,” dated August 1990,
established thirteen benefit areas labeled A through M (see Figure 2), and the city adopted one-
time capacity charges in each benefit area.
Each sewer benefit area overlays a specific sewer basin, defined as an area tributary to a
portion of the wastewater collection system where sewage flows to a common point, such as a
sewer pumping station or to an interceptor sewer. These benefit areas were established in
2 An EDU is a unit of measure representing the amount of sewer flow generated from a typical single-family
dwelling unit. For commercial and industrial properties, the city’s conversion is 1 EDU per 1,800 square-feet of
building floor space. EDUs by structure type and uses are listed in Carlsbad Municipal Code Section 13.10.020.
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largely undeveloped portions of the city’s
sewer service area at the time of the 1986
General Plan. The Village, Barrio, North
Beach, and northern Olde Carlsbad were not
included in the SBA program because their
sewer systems were largely constructed and
funded via assessment districts prior to the
creation of the SBA program. These
neighborhoods are currently experiencing
rapid new development and redevelopment
at densities that exceed those estimated in
the city’s 2019 Sewer Master Plan Update
and in the 2019 Village and Barrio Master
Plan adopted by the city.
2.4 State Housing Laws
State housing laws are a principal driver for
the proposed and projected development and
redevelopment activity that is occurring and is projected to continue occurring within the Study
Area. Some of these laws are described briefly for the purpose of explaining the development
type, density, or standards that are now possible under these new laws and the potential
impact on the City’s ability to impose sewer capacity or connection fees on new development.
2.4.1 Density Bonus Law
Originally enacted in 1979, California’s Density Bonus Law (Gov. Code sections 65915 - 65918)
allows housing and mixed-used developments to increase density on a property above the
maximum set under a jurisdiction’s General Plan land use plan. Generally, in exchange for the
increased density, qualifying projects can receive reductions in required development
standards, including those for necessary sewer facilities.
Density Bonus Law encourages the development of affordable and senior housing and provides
for up to a 50% to 80% increase in project densities depending on the amount of affordable
housing provided with unlimited density available for certain transit-adjacent, 100-percent
below market rate projects. Further, the law contains three provisions that require local
governments to grant qualifying projects incentives (or concessions) that provide cost
reductions, or waivers of development standards that would physically preclude the
development of a project at the density permitted and with the incentives granted (Southern
California Association of Governments, 2024).
2.4.2 Housing Accountability Act
The Housing Accountability Act (HAA) enacted in 1982, Government Code section 65589.5,
establishes limitations to a local government’s ability to deny, reduce the density of, or make
infeasible housing development projects, emergency shelters, or farmworker housing that
FIGURE 2. SEWER BENEFIT AREAS, 1990.
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contribute to meeting housing needs and are consistent with objective local development
standards. Sewer capacity is one such development standard which can be conditioned upon a
development project if the granting of an incentive would have a specific, adverse and
unavoidable impact on public health or safety. Recent amendments to the HAA expand and
strengthen its provisions in recognition of the state’s housing needs, streamlining the
permitting process and limiting the applicability of development standards. These include
California Senate Bill 330, signed into law as part of the Housing Crisis Act, and other recent
legislation.
2.4.3 Senate Bill 330
Senate Bill 330 allows for the filing of a preliminary application, making a housing development
project subject only to the ordinances, policies, standards, or any other measure adopted and
in effect when a preliminary application was submitted. These include a general plan,
community plan, specific plan, zoning, design review standards and criteria, subdivision
standards and criteria, and any other rules, regulations, requirements, and policies of a local
agency, as defined in Government Code section 66000, including those relating to development
impact fees, capacity or connection fees or charges, permit or processing fees, and other
exactions. However, there are some circumstances where the housing development project can
be subjected to a standard beyond those in effect when a preliminary application is filed:
• In the case of a fee, charge, or other monetary exaction, an increase resulting from an
automatic annual adjustment based on an independently published cost index that is
referenced in the ordinance or resolution establishing the fee or other monetary
exaction.
• A preponderance of the evidence in the record establishes that the standard is
necessary to mitigate or avoid a specific, adverse impact upon public health or safety,
and there is no feasible alternative method to satisfactorily mitigate or avoid the
adverse impact
2.4.4 Government Code section 66311.5
Government Code section 66311.5 limits a local agency’s ability to apply connection fees and
capacity charges to accessory dwelling units (ADUs) and junior ADUs. In general, a local agency
shall not require the applicant to install a new or separate utility connection directly between
an ADU and the public utility, or impose a related connection fee or capacity charge, unless the
ADU was constructed with a new single-family dwelling, or upon separate conveyance of the
ADU pursuant to Section 66342. A connection fee or capacity charge shall be proportionate to
the burden of the proposed ADU, based on its square footage or drainage fixture unit as
compared to the primary dwelling.
2.5 Report Organization
The assumptions and methodology for hydraulic evaluation of the sewer collection system are
described in a technical memorandum (Appendix A) which summarizes the following:
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• Land use and zoning within the benefit area
• an assessment of the existing development density (in EDUs)
• estimates of future development density, in EDUs
• the hydraulic analysis methodology and assumptions used to estimate sewer demand
and the hydraulic capacity of the existing sewer collection system
• the proposed sewer improvements necessary to convey the sewer demand added by
the future development
Section 3 of this report provides a general description of the Study Area
Section 4 summarizes the hydraulic evaluation for the level of future development density
assumed for the Study Area.
Section 5 recommends the Sewer Benefit Area N fee and describes the methodology for
establishing the fee, the factors influencing the costs estimated for the proposed sewer
improvements identified in Appendix A.
Section 6 lists considerations for future revisions to the Sewer Benefit Area N fee.
3 Study Area Description
The Study Area includes the neighborhoods of the Village, Barrio, North Beach, and portions of
Olde Carlsbad. The Study Area includes the following two main regions (see Figure 3):
• The area west of I-5 and bounded by Buena Vista Lagoon to the north, Agua Hedionda
Lagoon to the south, and the Pacific Ocean to the west. This area is generally comprised
of the Village, the Barrio and North Beach neighborhoods.
• The area east of the I-5 includes the collection system tributary to the Village & Barrio
area. This area occupies most of the Olde Carlsbad neighborhood and is generally
bounded by Buena Vista Lagoon to the north, Tamarack Avenue to the south, and
extends eastward almost to El Camino Real.
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FIGURE 3. STUDY AREA.
The sewer flow generated in these regions discharges to the city’s sewer collection system and
ultimately to the Vista/Carlsbad Interceptor (VCI) via eight direct connections. The connections
to the VCI occur at the following locations:
• Jefferson St, south of Laguna Dr
• Jefferson St, south of Grand Ave
• North County Transit District (NCTD) right-of-way at Walnut Ave
• NCTD right-of-way at Chestnut Ave
• NCTD right-of-way at The Village Apartments
• NCTD right-of-way at Chinquapin Ave
• NCTD right-of-way at Date Ave
• NCTD right-of-way at Aguila St
Sewer flow tributary to the Home Plant Lift Station is pumped to a high point in the sewer
collection system, a sewer access hole where the flow “breaks” or transitions from pressure
flow to gravity flow, and then flows by gravity to the VCI at Jefferson St/Laguna Dr. Similarly,
sewer flow tributary to the Chinquapin Lift Station is pumped to the intersection of Chinquapin
Ave and Garfield St, where it then flows by gravity via Garfield St, Acacia Ave, and Washington
St to the VCI.
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Additional information on the Study Area and the sewer collection system is provided in
Appendix A. A map of the parcels within the Study Area is provided in Appendix B.
3.1 Local Facilities Management Zones
Carlsbad is divided into twenty-five local facilities
management zones, or LFMZs (Figure 4) as part of the
city’s Growth Management Program which tracks
development activity throughout the city. The Study Area
occupies a large portion of LFMZ 1 which is generally
situated north of the Agua Hedionda Lagoon and west of
El Camino Real. A map depicting the Study Area in
relation to LFMZ 1 is provided in Appendix B.
The most recent Growth Management Program
Monitoring Report identifies residential dwelling unit
activities by LFMZ and by quadrant. The city’s Northwest
Quadrant consists of six zones including LFMZ 1 where
development activity was most active for the fiscal year
2024-25 reporting period. Of the total 136 building
permits issued for dwellings, 96 (71%) were primary dwellings and 40 (29%) were ADUs. The
monitoring report provides a five-year review of residential building permits issued, including
ADUs, which is shown in Figure 5. The data suggests a 30% decrease from the prior fiscal year
reporting period in building permits issued for dwelling units.
3.2 Density Bonus Yield
In January 2025, staff reviewed
development reports and pending
development applications to
conduct a yield analysis of density
bonus sites. The density bonus yield
was estimated as the ratio of the
proposed development density
divided by the maximum density allowed without density bonus.
The analysis estimated yields of 143% for the downtown area (generally defined as the area
west of I-5), 110% outside the downtown area, and 119% citywide. The point-in-time analysis
did not conform with a specific time period and considered projects under active review at that
time. The LFMZ data and yield analysis provide insight into the level of development activity
and density bonus that is occurring with the Study Area and the city.
FIGURE 4
FIGURE 5
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4 Summary of Hydraulic Evaluation
4.1 Sewer Flow Scenarios
The hydraulic evaluation of the sewer collection system consists of hydraulic modeling of the
projected sewer demand as follows:
• Existing System Flows. Existing system flows based on current EDU count estimates
within the Study Area. The estimated total EDU count for existing conditions is 9,414
EDUs, summarized in Tables 1 and 2 by improvement group. When adjusted to account
for development which has occurred since the 2019 Sewer Master Plan (359 EDUs), the
EDU count for fee determination purposes is 9,055 (refer to Appendix A, Section 4.1).
• Village & Barrio Maximum Density Scenario. Existing system flows plus maximum
projected land use densities for all Village & Barrio Master Plan parcels.
• Density Bonus Scenario. Same as the Village & Barrio Maximum Density Scenario but
with all flows within the study area modeled with a 20% increase to account for density
bonus, consistent with the citywide yield stated in Section 3.2. The estimated total EDU
count for the study area for the Density Bonus Scenario is 15,515 EDUs.
The total count of EDUs to be added to the sewer collection system within the Study Area and
for the Density Bonus Scenario is 6,460 EDUs.
Appendix A, Section 4 describes the land use and zoning assumptions used for estimating the
EDU count and sewer generation rates. The EDU counts are summarized in Table 1 by
improvement group, or portions of the sewer collection system where capacity improvements
are identified.
Table 1. Tributary EDUs per Improvement Group
Improvement Group
Existing
Conditions
Density Bonus
Scenario
Carlsbad Village Station* 1,027 2,569
Chestnut, Roosevelt, Magnolia 1,984 2,997
Harding St & Grand Ave 2,283 2,820
Jefferson Street 723 871
Washington St 1,344 1,628
Total: 7,361 10,885
* Carlsbad Village Station is tributary to Home Plant LS
In addition to the improvement groups in Table 1, there are several sewer groups that do not
require additional sewer capacity based on the development patterns and densities assumed in
the hydraulic evaluation. These groups flow through the city’s wastewater collection system
and ultimately to the VCI and are summarized in Table 2.
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Table 2. Tributary EDUs for Sewer Groups with no Improvement
Sewer Group
Existing
Conditions
Density Bonus
Scenario
Laguna Drive 361 474
The Village Apartments* 174 487
Aguila Street 308 380
Date, Olive, Garfield 53 151
Chinquapin Ave 129 155
Home Plant Lift Station (not
tributary to Carlsbad Village
Station improvement group)
1,028 2,877
Total: 2,053 4,524
* Private system
Appendix A, Section 5 describes the influence of rainfall-derived inflow and infiltration (i.e., wet
weather inflow and infiltration into the sewer collection system) on the calculated sewer flows.
The Density Bonus Scenario with inflow and infiltration has a significant effect on Home Plant
Lift Station and the recommended improvement to provide capacity for the flow increase is
discussed in Section 5 of this report.
Appendix A, Section 6 describes the methodology and presents the results of the hydraulic
evaluation of the sewer collection system for the projected Density Bonus Scenario for both dry
weather flow and wet weather flow design criteria.
4.2 Sewer Improvement Groups
The sewer collection system serving the Study Area has reached its design capacity per the
city’s engineering standards. Appendix A, Section 6.2 identifies the sewer system improvement
groupings that require sewer system capacity improvements for the Density Bonus Scenario.
The sewer system improvement groups requiring capacity improvements are listed below and
maps of the improvement reaches and tributary areas are contained in Appendix A:
• Carlsbad Village Station
• Chestnut, Roosevelt, Magnolia
• Harding St and Grand Ave
• Jefferson St
• Washington St (including Garfield Ave)
• Home Plant Lift Station
The required improvements are correlated with the assumptions on development density,
specifically, the locations of development projects and the density bonus assumed for each
project. The improvements will vary if development patterns or densities differ from the
assumptions used in the hydraulic modeling and can yield additional sewer improvement
groups. Under the Density Bonus Scenario, it is necessary to upgrade 1.98 miles of sewer
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gravity mains with larger diameter pipe and upgrade the Home Plant Lift Station. The
improvement summary is provided in Table 3.
Table 3. Sewer Gravity Main Improvement Summary
Improvement Group
Length of Improvement
(lineal feet)
Carlsbad Village Station 541
Chestnut, Roosevelt, Magnolia 2,547
Harding St & Grand Ave 2,743
Jefferson St 1,368
Washington St 3,264
Home Plant LS* - -
Total (feet) 10,463
Total (miles) 1.98
* Wet well improvements, see Section 5.2
4.3 Scoping and Phasing Considerations
Factors to be considered in the scoping and phasing of future capital improvement program
(CIP) projects include:
• the spatial variability of future development projects, or the clustering or concentration
of projects within the Study Area
• the density bonus and associated sewer flow increase that may apply to specific
development projects
• the time horizon for full development of the Study Area to the levels assumed in
the four sewer loading scenarios
• the method of construction and complexity of sewer CIP projects
• the capital funding requirements for sewer CIP projects considering escalation for
inflation, prioritization, and phasing
• city or California Coastal Commission permit procurement timelines or construction
scheduling requirements
Development permit streamlining and environmental exemptions allowed under state-
mandated housing laws have accelerated the development project permitting process. City
sewer improvement projects, however, do not benefit from these exemptions and may take
years for permitting and implementation. Redevelopment projects, often involving the merger
of two or more single-family residential parcels into a single, larger parcel for multi-family or
mixed-use developments, present the greatest uncertainty in sewer demand projections and
the required sewer system improvements. These variables necessitate continued flow
monitoring of the sewer collection system to evaluate, in conjunction with hydraulic modeling,
the required capacities and implementation schedules for sewer improvement projects.
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5 Capacity Fee Determination
5.1 Methodology
The method used for capacity fee determination is based on the incremental method in which
new development, including redevelopment, that adds sewer demand on the collection system
should pay for the additional capacity necessary to serve new development. This method is
considered appropriate when a significant portion of the capacity required to serve new sewer
demands must be provided by the construction of new or upsized facilities. This applies to the
proposed SBA N as evidenced by the city’s prior sewer master plans which did not identify the
need for capacity improvements to serve new development under their Existing Condition or
Build-Out evaluation scenarios. Further, the results of the hydraulic modeling analyses for new
sewer demands (Appendix A) supports the need for capacity improvements to serve new
development.
Under this incremental method, the costs for system capacity improvements are allocated to
new development based on their demand or capacity requirements, i.e., on an EDU basis,
regardless of the value of past investments made in the collection system by existing
customers.
5.2 Cost Estimates
The cost estimates developed for the sewer collection system improvements are based on city
sewer CIP projects of similar scope constructed within the past five years. The factors
considered in the cost estimates include the following:
• pipe material costs
• sewer trench widths
• trench depth and excavation and backfill volumes
• trench shoring
• temporary sewer bypassing
• groundwater dewatering of the sewer trench
• rehabilitation of access holes where larger pipe penetrations are needed
• traffic control
• pavement restoration
The following assumptions are used to develop unit costs for sewer pipeline construction:
• Excavation and backfill volumes for trench excavations are based on standard trench
widths and excavating equipment.
• Materials excavated from the trench are suitable for reuse in trench backfill.
• Trench shoring costs are based on the length-weighted, average trench depth of all pipe
segments in each sewer improvement group.
• Each sewer improvement group is assumed to be constructed as one phase.
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• Temporary sewer bypass system costs assume the total length of the sewer
improvement group and multiple bypass setups if the total length of construction
exceeds 700 feet.
• Rehabilitation of sewer access holes is included as some damage will occur to access
holes with the installation of larger pipe. Rehabilitation is assumed to consist of a non-
structural epoxy coating and replacement of access hole frames and covers. The cost to
replace existing access holes is not included in the cost estimates.
• Groundwater dewatering is required, and groundwater is not contaminated and can be
discharged to the public sewer without hazardous materials treatment.
• Pavement restoration is assumed to consist of two lanes where the sewer alignment is
situated on the centerline of a two-way street.
• Relocation of public or franchise utilities is not required.
The construction cost estimates represent a Class 4 estimate according to the Association for
the Advancement of Cost Engineering (AACE), which is used for study or feasibility purposes
and has an expected accuracy range of -20 to +30 percent. The estimates are based on bid data
from past sewer construction projects in Carlsbad, factored to the present day for inflation
using the Engineering News-Record Construction Cost Index, Los Angeles region. Engineering
site evaluations for geotechnical conditions have not been conducted, and preliminary plans
have not been prepared, and sewer construction is assumed to have “no conflict” with other
utilities or infrastructure. The cost estimates include a 30% contingency on the construction
costs to account for unknown site conditions and the feasibility level analysis. The cost
estimates for each sewer improvement group are summarized in Table 4 and additional detail is
provided in Appendix C.
Table 4. Cost Summary
Improvement Group Total Cost ($)
Carlsbad Village Station 4,011,485
Chestnut, Roosevelt, Magnolia 4,012,201
Harding St & Grand Ave 5,589,559
Jefferson Street 2,709,680
Washington St 11,906,289
Home Plant LS 2,525,264
Total: 30,754,478
Other costs include engineering design; geotechnical and environmental studies; cultural and
archaeological resources monitoring during construction; construction management and
inspection; special inspection of construction materials; public outreach; and plan review and
right-of-way inspection fees. Right-of-way permit, plan review and inspection fees are
estimated in accordance with the city’s Master Fee Schedule (FY 2025-26).
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Utility encroachments in North County Transit District right-of-way are subject to fees for
permits, support services during construction, and incidental use of the right-of-way. These fees
are listed in the NCTD Board Approved Cost Recovery Schedule and are subject to annual
adjustment. Support services include training for all contractor employees conducting work in
the NCTD right-of-way, and railway flagging protection. The incidental use fee includes a one-
time setup fee and annually recurring administration and license fees. The license fee varies by
casing pipe diameter, length of installation, and the type of encroachment (crossing or parallel
encroachment). For SBA N, the encroachment types consist of a pipeline crossing at Carlsbad
Village Station and a parallel installation at Washington St. These fees are included in the cost
estimates because the work to replace the existing sewer pipes with larger pipes will invalidate
the existing NCTD licenses, causing the issuance of new licenses in accordance with the current
cost recovery schedule. The present worth of the annual recurring fees assumes an annual
escalation of 3%. Note that the annual Consumer Price Index for All Urban Consumers (CPI-U)
for San Diego-Carlsbad, CA, not seasonally adjusted, is an average of 2.8% over the past 20
years, and 4.4% from 2020 through 2025. The one-time fees and the present worth of the
annual recurring fees are shown in the cost estimates.
In locations where the sewer invert depth and the resulting excavation exceeds 25 feet below
ground surface or where construction will occur beneath railroads, freeways, or prime arterial
streets, trenchless construction methods are assumed in the cost estimates. Trenchless
construction carries a premium cost which varies by length of boring or tunnelling; geotechnical
conditions such as large cobble, hard rock formations, or the occurrence of groundwater; the
depths of jacking/entry or receiving/exit pits; and the complexity of site constraints such as
potential conflicts with existing utilities or traffic control. The unit cost of trenchless
construction is based on March 2024 contract costs for a 105 lineal-foot bore-and-jack
installation of 12-inch diameter carrier pipe in a 24-inch diameter casing with six feet of cover
at $2,400 per LF and jacking and receiving pits at $72,000. For comparison, the trenchless
installation in the Carlsbad Village Station improvement group is 17 feet deep.
Capacity improvements at the Home Plant Lift Station are needed to mitigate peak wet weather
flows. The alternatives considered to manage the station’s peak inflow consist of adding
storage volume to the lift station wet well or replacing the pumps and electrical gear in the lift
station and the 2,130-lineal foot, dual force main pipelines in Laguna Drive. Laguna Drive east of
State Street is occupied with numerous wet and dry utilities. Off-site improvements in Laguna
Drive carry a higher cost and utility alignment conflict risk than constructing a larger wet well at
the lift station and, therefore, a larger wet well is assumed in the cost estimates for the Home
Plant Lift Station sewer improvement group.
Because site-specific factors that may influence cost and project implementation schedules are
unknown during the development of planning-level cost estimates, the cost estimates should
be reviewed upon completion of preliminary design or when project implementation schedules
are determined and the cost estimates revised if warranted.
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5.3 Recommended Capacity Fee
Based on the assumptions and methodology described in this report, the sewer collection
system improvements identified for the Density Bonus Scenario should be considered for
implementation. An estimated count of 6,460 EDUs, consistent with the Village and Barrio
Master Plan plus a 20% density bonus, is recommended as the basis for the proposed SBA N
fee. Under this methodology, as demonstrated by this study, the fee will not exceed the City’s
estimated reasonable costs of providing sewer infrastructure to serve new development. The
recommended fee is as follows:
Density Bonus Scenario
Total cost of improvements: $30,754,478
EDUs 6,460
SBA N fee per EDU: $4,761
The proposed fee will be imposed on new development and redevelopment in proportion to a
development’s sewer demand will be used to fund the proposed sewer system capacity
improvements in SBA N as described in this engineering report or revisions hereto as may be
approved and adopted by the Carlsbad City Council. Annual adjustment of the fee should occur
due to changes in regional construction costs using the Engineering News-Record, Construction
Cost Index, Los Angeles region. The annual adjustment for other sewer benefit area fees is
typically accomplished using the January-to-January change in the index.
5.4 Accessory Dwelling Units (ADUs) and Junior ADUs
In accordance with Government Code Section 66311.5(b) and (e), the SBA N fee will apply to
accessory dwelling units if a new or separate sewer connection to the public sewer is required
and the ADU is detached and constructed with a new single family dwelling.
The amount charged shall be proportionate to the size of the ADU, in square feet, or the
number of drainage fixture unit (DFU) values. Accordingly, the sewer capacity charge for an
ADU shall be the SBA N fee divided by 1,800 square feet, multiplied by the ADU floor area. As
an example, the per-square-foot charge would be $4,761/1,800 (or $2.65/SF), and the SBA N
charge for a 1,200 square-foot ADU would be $3,180.
Junior accessory dwelling units (JADU), as defined in Government Code Section 65852.22, will
be exempt from the SBA N fee. A JADU is defined as a unit that is no more than 500 square feet
in size and contained entirely within a single-family residence. A junior accessory dwelling unit
may include separate sanitation facilities or may share sanitation facilities with the existing
structure.
6 Future Revisions
The EDUs estimated for build-out in this report consider the development densities listed in
development project applications, the approved General Plan land use and zoning, and density
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bonus assumptions based on recent yield (units per acre) for development projects in the Study
Area. Greater densities are possible per existing state housing laws.
This report does not grant approval for new sewer connections or increased development
densities to any existing sewer connection within the Study Area and such proposals will
require evaluation for potential sewer capacity impacts on a case-by-case basis.
Changes in development patterns, density, or type will necessitate revisions to the SBA N EDU
count and revised flow estimates for adequate sizing of sewer system facilities. Changes in unit
count and sewer flow may also occur due to construction of non-residential buildings, tenant
improvements, ADUs or JADUs, and increased student enrollment at schools. These increases
are uncertain and unpredictable. Changes in local planning regulations and state housing laws
also have the potential to increase density allowances and sewer demands. As such,
subsequent review of the Study Area and governing regulations should be conducted at least
once every five years.
* * *
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APPENDIX A
TECHNICAL MEMORANDUM
FOR
VILLAGE & BARRIO AREA DENSIFICATION
COLLECTION SYSTEM MODELING
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Village & Barrio Area
Densification Collection
System Modeling
City of Carlsbad Utilities Department,
Engineering Division
Carlsbad, CA
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9/30/20269/30/20200066
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Contents
1. Introduction..........................................................................................................................................1
2. Background .........................................................................................................................................1
3. Study Area...........................................................................................................................................2
4. Projected Sewer Flows........................................................................................................................3
4.1 Existing System Conditions.......................................................................................................3
4.2 Village & Barrio Maximum Density............................................................................................4
4.3 Density Bonus Scenario............................................................................................................5
5. Modeled Wet Weather Flows..............................................................................................................7
6. Hydraulic Model Analysis ....................................................................................................................7
6.1 Evaluation and Design Criteria..................................................................................................7
6.2 Results & Recommended Improvements..................................................................................8
6.2.1 Collection System Capacity Results & Improvements.................................................8
6.2.2 Areas with No Improvements.....................................................................................13
6.2.3 Lift Station Capacity Results & Improvements...........................................................17
7. Conclusions.......................................................................................................................................19
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Tables
Table 1. Assumed VBMP Parcel Densities and Sewer Flow Rates .............................................................4
Table 2. Developments and General Plan Proposed Rezone Sites EDU Count..........................................5
Table 3. Gravity Mains Recommended Improvements Summary................................................................9
Table 4. Tributary EDU Improvement Groups Summary..............................................................................9
Table 5. EDUs per Interceptor Tributary Areas with No Improvements .....................................................13
Table 6. Lift Station Model Flow Rate Results............................................................................................17
Table 7. Lift Station Modeled Tributary EDUs per Scenario.......................................................................17
Figures
Figure 1. Village & Barrio Area within the City of Carlsbad ..........................................................................1
Figure 2. Study Area Boundary and Lift Station Tributary Areas..................................................................2
Figure 3. Developments and General Plan Proposed Rezone Sites............................................................6
Figure 4. Density Bonus Scenario Improvements ......................................................................................10
Figure 5. Improvement Group Tributary Areas...........................................................................................11
Figure 6. Interceptor Tributary Areas, No Improvements ...........................................................................15
Figure 7. Lift Station Tributary Areas ..........................................................................................................18
Appendices
ID Name
A Detailed Model Results
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1. Introduction
This technical memorandum (TM) summarizes the hydraulic model analysis performed for the City of
Carlsbad Utilities Department to evaluate system capacity for future sewer flow conditions due to
redevelopment and increased development density in the Carlsbad Village and Barrio area and
nearby coastal areas in the City of Carlsbad (City). Services for this task were conducted under the
Master Agreements for Utility Modeling Services, PSA22-1964CA and PSA25-3768CA.
2. Background
In late 2016, the City of Carlsbad commissioned HDR to complete updates for the Citys Potable
Water, Recycled Water, and Sewer Master Plans. The master plan updates were completed in
2019. As part of the updates, the Citys hydraulic models were updated to perform planning level
analysis of the Citys water, sewer, and recycled water systems. For the updates to the Citys Sewer
Master Plan (SMP), the Citys
InfoSWMM®sewer model (Master
Plan Model) was updated with
current infrastructure and sewer
flow estimates.
In August 2019, the Village and
Barrio Master Plan (VBMP) was
adopted by City of Carlsbad. The
VBMP outlines future development
for the Village and Barrio area
shown in Figure 1. The VBMP
assigns a general land use type
with a density range to each parcel
in the Village & Barrio footprint.
In addition to the master plan
studies, the City is experiencing
redevelopment as a result of a
State of California mandated
Housing Element decree and
related laws which allow for
increased housing densities
beyond what is accounted for in
the SMP and VBMP projections,
with density bonuses and an
increase in auxiliary dwelling units
(ADUs) on residential properties.
Figure 1. Village & Barrio Area within the City of
Carlsbad
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3. Study Area
This study includes updates to dry weather flow loading for the project evaluation study area (Study
Area) based on available data and planning documents. This study will include the collection system
and parcels in the Study Area shown in Figure 2. The Study Area is split into two sections. The
Study Area West of Interstate Highway 5 (I-5) is bound by I-5 to the east, Buena Vista Lagoon to the
north, Agua Hedionda Lagoon to the south, and the Pacific Ocean to the west. The Study Area East
of the I-5 includes the collection system tributary to the Village & Barrio area.
As shown in Figure 2, a large portion of the Village & Barrio area is served by the Home Plant Lift
Station (LS). The adjacent coastal area to the south is served by the Chinquapin LS or gravity flows
directly to the Vista-Carlsbad Interceptor (VCI).
Figure 2. Study Area Boundary and Lift Station Tributary Areas
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4. Projected Sewer Flows
This section discusses projected dry weather customer sewer flows served by the Study Area
collection system. The following section discusses the wet weather component sewer flows included
in the hydraulic model analysis.
To evaluate the potential effects of the implementation of the VBMP and possible redevelopment of
Study Area parcels resulting in densification, projected sewer flows were calculated based on
planned near-term developments and land use density estimates from the VBMP. Tributary land
use outside of the VBMP footprint were based on the latest landowner and land use parcel data
including information relating to recent developments.
Due to uncertainties in ultimate densities of parcels and development patterns in the study area,
including possible density bonuses and an increase in auxiliary dwelling units (ADUs) on residential
properties, sewer model flow loading estimates were developed to include the following components:
Existing System Flows. Based on current equivalent dwelling unit (EDU) count estimates
with flows generated based on the assumption that each EDU generates 200 gallons per day
(gpd) of wastewater flows.
VBMP Maximum Density Flows. Projected land use-based sewer flows for VBMP area
parcels, assuming maximum density for all VBMP parcels.
Density Bonus Scenario. Existing and VBMP Maximum Density flows plus a 20 percent
density bonus to account for potential densification. This scenario includes planned near-
term developments, many of which include density bonus.
Flow loading components are discussed in more detail in the following sub-sections.
4.1 Existing System Conditions
For a more accurate representation of existing conditions within the Study Area boundary, dry
weather flow loading from existing residential properties were updated in the model based on the
Citys current assessor parcel layer. The parcel layer was used to calculate EDU count and
locations. The estimated EDU count in the hydraulic model for the existing condition scenario is
9,414 EDUs and is summarized by tributary area in Table 4 and Table 5. This EDU count includes
the 35 EDUs associated with building permits that have been issued since the 2019 SMP in which
only one pipe segment in the sewer collection system Study Area was identified as requiring a
capacity upgrade. Section 6.2 of this report describes the findings of the 2019 SMP. To account for
the 35 EDUs associated with recent building permits, and to be consistent with the 2019 SMP
analysis, 35 EDUs were deducted from the overall Study Area EDU count estimate. Therefore, the
resulting EDU count for the existing conditions to be used for fee purposes is 9,055.
A sewer generation rate of 200 gpd per EDU, in accordance with the Carlsbad Engineering
Standards, was used to estimate current dry weather flow loading. Additionally, dry weather sewer
flows from non-residential properties were calculated based on General Plan land use types and per
acre loading rates from the SMP. Flow rates per land use type are summarized in Table 3-11 of the
SMP. The updated residential and non-residential flows were then loaded onto the Master Plan
Model within the Study Area. To account for dynamic flow loading, updated flows were assigned
diurnal patterns from the SMP based on land use type. Residential flows were assigned a residential
diurnal pattern, and non-residential flows were assigned a commercial diurnal pattern.
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4.2 Village & Barrio Maximum Density
The VBMP includes eight districts, each with its own land use description and projected dwelling unit
density range. Baseline VBMP area sewer flow projections for this study were developed by
assuming the highest dwelling unit density for each parcel in each district. Densities were converted
to sewer flows using criteria from the SMP which assumes 200 gpd per EDU for all land use types
within the VBMP area. Projected sewer flow for each VBMP parcel were spatially loaded to the
Master Plan Model. Estimated sewer flow rates per district and use type are summarized in Table 1.
Additionally, VBMP land use types were characterized as either residential or commercial based on
descriptions included in the VBMP, and residential or commercial diurnal patterns from the SMP
were assigned to modeled sewer flows accordingly. Assumed general land use types for the VBMP
district land use types are included in Table 1.
Table 1. Assumed VBMP Parcel Densities and Sewer Flow Rates
Village & Barrio Master Plan District
Maximum
Density a General Land Use
Type b
Sewer Flow Rate
c
District Name Abbreviation (EDU/acre)(gpd/acre)
Village Center VC 35 Commercial 7,000
Village General VG 23 Commercial 4,600
Hospitality HOSP 23 Commercial 4,600
Freeway Commercial FC 35 Commercial 7,000
Pine-Tyler Mixed-Use PT 23 Commercial 4,600
Barrio Perimeter BP 30 Residential 6,000
Barrio Center BC 15 Residential 3,000
Village-Barrio Other d VBO Not applicable
a Maximum density for each district selected from 2019 Village & Barrio Master Plan, Table 2-2
b Either Residential or Commercial selected as general land use type based on district description in 2019 Village & Barrio
Master Plan, Section 2.2.2
c Calculated based on density assumption and 200 gpd/EDU assumption from 2019 Carlsbad Sewer Master Plan, Section 3.2.3
d Village-Barrio Other district parcels assumed to not be developed as part of the VBMP per 2019 Village & Barrio Master Plan,
Section 2.2.2
Projected sewer flow rates from the Master Plan Model were also applied to the Village-Barrio
Other district parcels in the VBMP area, as the VBMP indicates that zoning for these parcels is
independent of the VBMP land use projections (Section 2.2.2 H). Flows from planned near-term
developments were included in the model flow loading. The General Plan (including the Final
Supplemental Environmental Impact Report (Final SEIR) for the Housing Element Implementation
and Public Safety Element Update) includes the Proposed Rezone Site 14 within the VBMP area.
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Table 2 lists other near-term
developments that are anticipated for the
Study Area and the estimated EDU
count used in the hydraulic model.
Development site locations are shown in
Figure 3.
4.3 Density Bonus
Scenario
In addition to the projected sewer flow
rates discussed above, a density bonus
was applied to the projected future
system flows. This density bonus
includes a 20 percent increase in the
projected future system flow rates to
account for densification from new
development, redevelopment or
additional ADUs. For the purposes of
this study, the current and projected
study area flow rates were multiplied by
a 1.20 factor to calculate flow rates for
the Density Bonus Scenario. The
estimated EDU count for the study area
for the Density Bonus Scenario is 15,515
EDUs.
These customer-based sewer flow
projections represent the dry weather
flow component of the hydraulic model
analysis. The wet weather component of
the model scenarios is discussed in the
following section.
Table 2. Developments and General
Plan Proposed Rezone Sites EDU Count
Developments & Proposed Rezone
Sites
Estimated EDU
Count
2618 Jefferson Laguna Vida 4
2620 Roosevelt Development 12
2647 Jefferson Street 18
Carlsbad Blvd Duplex Project 4
Carlsbad Village Mixed Use 327
Carlsbad Village Square 5
Cherry Beach Homes 3
CVO Rincon 75
Devries Triplex 3
Harding Palm Townhouses 6
Harding Street Apartments 10
Hope Apartments 234
Jefferson 16 36
Jefferson Street Homes 12
Juniper Coast Homes 31.5
Maple Duplex 2
Normandy Beach Homes 2
Ocean Street Residence 2
Proposed Rezone Site 14 250
Rincon Garfield 2
Rincon Roosevelt 49.5
Roosevelt Condos 12
The Roosevelt 12
Timm Residence 3
Tyler Street Homes 12
May 12, 2026 Item #13 Page 38 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
FINAL - April 27, 2026 |6
Figure 3. Developments and General Plan Proposed Rezone Sites
May 12, 2026 Item #13 Page 39 of 89
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Village & Barrio Area Densification Collection System Modeling TM
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FINAL - April 27, 2026 |7
5. Modeled Wet Weather Flows
The Master Plan Model as developed for the SMP was used as the basis for this hydraulic analysis.
The hydraulic model uses two components for estimating sewer flows in the collection system,
including dry weather or customer-based flows, discussed in the previous section, and wet weather
rainfall-derived inflow and infiltration (RDII) flows associated with a design rainfall event.
The SMP model represents RDII based on a design storm intensity of a 10-year, 24 hour event for
the area which is estimated at 2.94 inches (NOAA Atlas 14, Volume 6, Version 2, Latitude: 33.1272°,
Longitude: -117.2816°). The design storm for the SMP model, and the RDII flow volume response
included in the model, were based on a rainfall event in December 2010. Details of the RDII model
flow estimates and calibration are included in the SMP Section 3.1.3.
The design storm and RDII system response developed for the SMP model were used for the wet
weather flow analysis included in this study. Additionally, recent lift station discharge flow meter data
for the Home Plant LS and the Chinquapin LS were reviewed to check lift station response to wet
weather flows within the study area. Under PWWF conditions, the Chinquapin LS was modeled to
represent the maximum lift station capacity of 400 gallons per minute (gpm) based on observed
flows from lift station pump flow meter data.
The Home Plant LS conveys flows via Laguna Drive to the VCI in Jefferson Street. Therefore, the
Home Plant lift station was modeled as conveying all PWWF inflows arriving at the lift station, with
the capacity evaluation performed by comparing modeled peak inflow with lift station pumping
capacity. The hydraulic analysis and evaluation criteria are discussed in the following section.
6. Hydraulic Model Analysis
The hydraulic model was updated to include the projected flow loading for the Density Bonus
Scenario discussed in Section 4. The scenario was run for wet weather flow conditions including the
RDII flows discussed in Section 5. Model results were evaluated for potential system hydraulic
deficiencies and improvements were developed based on the criteria outlined below.
6.1 Evaluation and Design Criteria
Model results were evaluated based on the City of Carlsbad Engineering Standards (Volume 1
General Design Standards, 2022 Edition (rev. Oct. 2, 2024), Chapter 6).
Model results for existing gravity mains were evaluated based on main depth-to-diameter (d/D)
criteria for PWWF conditions. Recommended gravity main upsizing was based on both dry weather
flow and wet weather flow criteria. The gravity main criteria used for this analysis include:
Peak Dry Weather Flow Conditions
All Gravity Mains: d/D must be less than 0.50
Peak Wet Weather Flow Conditions
All Gravity Mains: d/D must be less than 0.75
Lift station capacity was also evaluated for peak flow conditions based on the Citys Engineering
Standards. The lift station capacity criteria used for this analysis include:
May 12, 2026 Item #13 Page 40 of 89
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City of Carlsbad Utilities Department, Engineering Division
FINAL - April 27, 2026 |8
Peak Wet Weather Flow Conditions
Lift Station < 3 MGD Capacity: Convey PWWF with standby pump offline
These criteria were used to identify system deficiencies and recommend improvements for the
analysis scenario.
6.2 Results & Recommended Improvements
A review of the 2019 SMP finds that one pipe segment was identified for capacity improvement due
to insufficient pipe slope. Sewer main SWM3653, in Basswood Ave east of Highland Dr, receives
sewer flow from a developed, single-family residential sewer subarea that also serves Carlsbad High
School. The 2019 SMP hydraulic analysis identified no other projects in the Study Area for the two
scenarios evaluated: the Near-Term Capacity Analysis, which consisted of the existing system plus
near-term projects, and the Buildout System Capacity Analysis (year 2040).
Model results were evaluated based on the criteria outlined in Section 6.1. Model results indicate
the Density Bonus Scenario results in hydraulic deficiencies under PWWF conditions per the
evaluation criteria. This subsection summarizes the modeled deficiencies. Collection system
capacity results are addressed in the following subsection, and lift station capacities are addressed
in the subsequent subsection. Detailed model results are included in Appendix A.
6.2.1 Collection System Capacity Results & Improvements
Model results indicate that Density Bonus Scenario results in gravity main hydraulic capacity
deficiencies in the sewer collection system per the PWWF evaluation criteria. In cases where
several mains in series may need to be upsized to avoid a reduction in pipe diameter to mitigate a
hydraulic bottleneck, the affected mains were included in groups of recommended system
improvements to satisfy the hydraulic design criteria. Recommended gravity main improvements are
summarized in Table 3 and described below. Tributary EDU counts per improvement group are
summarized in Table 4. The improvement groups for the Density Bonus Scenario are shown in
Figure 4. Tributary areas for the improvement groups are shown in Figure 5.
Figure 4 shows gravity main improvement groupings for the Density Bonus scenario, which includes
VBMP flows and all model Study Area and tributary flows increased by an additional 20 percent.
There are five improvement groupings for this scenario which include a total of approximately 1.98
miles of upsized gravity mains. The recommended improvement groups for the gravity sewer mains
include:
Carlsbad Village Station
Chestnut, Roosevelt, Magnolia
Harding St and Grand Ave
Jefferson St
Washington St and Garfield Ave
Lift station improvement groupings are discussed later in the subsection titled, Lift Station Capacity
Results & Improvements.
May 12, 2026 Item #13 Page 41 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
FINAL - April 27, 2026 |9
Table 3. Gravity Mains Recommended Improvements Summary
Length of Gravity Main Improvements (feet)
Improvement Group Density Bonus
Scenario
Carlsbad Village Station 541
Chestnut, Roosevelt, Magnolia 2,547
Harding St & Grand Ave 2,743
Jefferson Street 1,368
Washington St 3,264
Total 10,463
Total (miles)1.98
Table 4. Tributary EDU Improvement Groups Summary
Improvement Group
Tributary EDUs per Improvement
Group and Scenario
Existing
Conditions
Density Bonus
Scenario
Carlsbad Village Station 1,027 2,569
Chestnut, Roosevelt, Magnolia 1,984 2,997
Harding St & Grand Ave 2,283 2,820
Jefferson Street 723 871
Washington St 1,344 1,628
Total 7,361 10,885
May 12, 2026 Item #13 Page 42 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
FINAL - April 27, 2026 |10
Figure 4. Density Bonus Scenario Improvements
May 12, 2026 Item #13 Page 43 of 89
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May 12, 2026 Item #13 Page 45 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
FINAL - April 27, 2026 |13
6.2.2 Areas with No Improvements
In addition to the collection system improvement tributary areas identified in Figure 5, some areas
gravity flow directly to the VCI along flow paths that are not identified to be in need of capacity
improvements based on the development patterns and densities assumed in the analysis. These
areas are shown in Figure 6 and are labeled as Laguna Drive, The Village Apartments, Aguila
Street, Chinquapin Ave, and Date, Olive, and Garfield. Estimated EDU counts for these areas are
summarized in Table 7.
Although this study does not indicate hydraulic capacity issues for these tributary areas, the sewer
collection system model analysis was performed based on assumptions about future system
conditions and the location and density of future developments. Therefore, future development
proposals in these areas should be evaluated for their potential impact on the sewer collection
system and compared with the assumptions of this study.
Table 5. EDUs per Interceptor Tributary Areas with No Improvements
Interceptor Tributary Areas
No Improvements
Existing
Conditions
Density Bonus
Scenario
Laguna Drive 361 474
The Village Apartments 174 487
Aguila Street 308 380
Date, Olive, Garfield 53 151
Chinquapin Ave 129 155
Home Plant Lift Station
(not tributary to Carlsbad Village
Station improvements)
1,028 2,877
Total 2,053 4,524
May 12, 2026 Item #13 Page 46 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
FINAL - April 27, 2026 |14
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May 12, 2026 Item #13 Page 47 of 89
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May 12, 2026 Item #13 Page 49 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
FINAL - April 27, 2026 |17
6.2.3 Lift Station Capacity Results & Improvements
Model results for peak wet weather inflows to the Home Plant LS and the Chinquapin LS are shown
in Table 6 and compared with the current firm lift station capacity as defined in the SMP. Table 7
shows modeled tributary EDUs for each lift station per scenario.
Model results for the Chinquapin LS indicate that inflows are projected to be less than the firm
capacity of the lift station. However, model results indicate that PWWF to the Home Plant lift station
is projected to exceed the lift station firm capacity for the Density Bonus Scenario.
Table 6. Lift Station Model Flow Rate Results
Lift Station Firm Capacity a
(gpm)
PWWF b per Model Scenario (gpm)
Existing
Conditions
Density Bonus
Scenario
Home Plant 1,000 937 1,663
Chinquapin 360 85 98
Red highlightsindicate modeled PWWF exceeds lift station firm capacity
aIndicates lift station capacity with largest pump offline, as listed in the 2019 Carlsbad Sewer
Master Plan, Table 2-3
b PWWF inflows with RDII based on design storm as described in Section 5.
Table 7. Lift Station Modeled Tributary EDUs per Scenario
Lift Station Existing
Conditions
Density Bonus
Scenario
Home Plant 2,054 5,473
Chinquapin 162 196
Increasing the pumping capacity of the Home Plant LS is expected to trigger improvements to the
pump stations mechanical and electrical systems and potentially the downstream force mains. An
alternative improvement may consist of the construction of a larger wet well to buffer peak wet
weather inflows. The evaluation of the improvement alternatives to handle the higher projected
inflows should consider the infrastructure impacts associated with each potential alternative. Such
evaluation is beyond the scope of this study.
May 12, 2026 Item #13 Page 50 of 89
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City of Carlsbad Utilities Department, Engineering Division
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Figure 7. Lift Station Tributary Areas
May 12, 2026 Item #13 Page 51 of 89
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FINAL - April 27, 2026 |19
7. Conclusions
The results for Density Bonus Scenario indicate most improvements are recommended for gravity
mains either upstream of the Home Plant LS or upstream of gravity main connections to the VCI.
These improvement groupings represent areas of the collection system where gravity sewer flows
converge for conveyance and the effects of increased development density and related sewer
demands are magnified. Approximately 1.98 miles of gravity main are recommended for upsizing for
the Density Bonus Scenario.
Additionally, model results indicate peak flows to the Home Plant LS are projected to exceed the lift
stations firm capacity for the Density Bonus Scenario. Future improvements which would increase
capacities of the pumping system, force mains, and/or the wet well should be evaluated and are
beyond the scope of this study.
May 12, 2026 Item #13 Page 52 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
Appendix A
Detailed Model Results
May 12, 2026 Item #13 Page 53 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-ii
Appendix A Table of Contents
1. VBMP Improvements Summary Table (A-1)
2. Carlsbad Village Station Improvement Group (A-2)
3. Chestnut, Roosevelt, Magnolia Improvement Group (A-6)
4. Harding St & Grand Ave Improvement Group (A-10)
5. Jefferson Street Improvement Group (A-14)
6. Washington St Improvement Group (A-18)
May 12, 2026 Item #13 Page 54 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-1
VBMP Area Projected Gravity Main Improvements for Density Bonus
Improvement Group Model ID Facility ID Length (ft)
Upsized Gravity
Main Diameter (in)
Carlsbad Village Station
194 SWM273 256 15
6384 SWM68 285 15
Improvement Group Length (ft)541
Chestnut, Roosevelt, Magnolia
4793 SWM5196 86 10
4792 SWM5195 218 10
202 SWM283 304 10
4890 SWM5293 306 10
6453 SWM4206 308 10
3880 SWM4217 368 12
3879 SWM4216 368 12
352 SWM443 47 15
388 SWM479 201 15
371 SWM462 341 15
Improvement Group Length (ft)2,547
Harding St and Grand Ave
6599 SWM6562 199 8
3906 SWM4274 350 8
6449 SWM4202 280 10
6481 SWM4270 241 12
6482 SWM4271 242 12
4858 SWM5261 17 15
4857 SWM5260 65 15
6483 SWM4272 239 15
6484 SWM4273 240 15
4864 SWM5267 380 15
6485 SWM4275 490 15
Improvement Group Length (ft)2,743
Jefferson Street
4870 SWM5273 322 10
4873 SWM5276 322 10
4871 SWM5274 330 10
4872 SWM5275 352 10
4867 SWM5270 42 12
Improvement Group Length (ft)1,368
Washington Street
6459 SWM4231 319 10
3891 SWM4236 345 10
3890 SWM4235 347 10
6461 SWM4233 349 10
6460 SWM4232 350 10
6462 SWM4234 355 10
200 SWM281 241 15
201 SWM282 241 15
3887 SWM4227 351 15
3888 SWM4228 366 15
Improvement Group Length (ft)3,264
Total Length (ft) 10,463
Total Length (miles) 1.98
May 12, 2026 Item #13 Page 55 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-2
Carlsbad Village Station Improvement Group: Gravity Main IDs
May 12, 2026 Item #13 Page 56 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-3
Carlsbad Village Station Improvement Group: Tributary Area
May 12, 2026 Item #13 Page 57 of 89
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Appendix A: Detailed Model Results
A-4
Carlsbad Village Station Improvement Group: Density Bonus Scenario Tabular Model Results
Model ID Facility ID Slope Length (ft)
Existing Diameter (in)
Upsized Diameter (in)
Tributary EDUs ADWF (mgd)PWWF (mgd)
d/D No Improve-ments
d/D With Improve-ments
q/Q No Improve-ments
q/Q With Improve-ments
194 SWM273 0.0002 256 12 15 2,568 0.514 1.120 0.87 0.70 3.48 1.92
6384 SWM68 0.0062 285 10 15 1,661 0.332 0.723 0.79 0.56 0.65 0.22
Carlsbad Village Station Improvement Group: Density Bonus Scenario HGL, No Improvements
Carlsbad Village Station Improvement Group: Density Bonus Scenario HGL, With Improvements
May 12, 2026 Item #13 Page 58 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-5
Carlsbad Village Station Improvement Group: Density Bonus Scenario Flows
Carlsbad Village Station Improvement Group: Density Bonus Scenario d/D, No Improvements
Carlsbad Village Station Improvement Group: Density Bonus Scenario d/D, With Improvements
May 12, 2026 Item #13 Page 59 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
May 12, 2026 Item #13 Page 60 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
May 12, 2026 Item #13 Page 61 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-8
Chestnut, Roosevelt, Magnolia Improvement Group: Density Bonus Scenario Tabular Model Results
Model ID Facility ID Slope Length (ft)
Existing Diameter (in)
Upsized Diameter (in)
Tributary EDUs ADWF (mgd)PWWF (mgd)
d/D No Improve-ments
d/D With Improve-ments
q/Q No Improve-ments
q/Q With Improve-ments
202 SWM283 0.0064 304 8 10 1,346 0.269 0.887 1.00 0.67 1.09 0.78
352 SWM443 0.0049 47 12 15 2,997 0.599 2.004 0.76 0.58 1.10 0.68
371 SWM462 0.0039 341 12 15 2,945 0.589 1.973 0.90 0.63 1.22 0.76
3879 SWM4216 0.0040 368 8 12 1,537 0.307 1.007 0.89 0.58 1.59 0.69
388 SWM479 0.0125 201 12 15 2,567 0.513 1.825 0.79 0.55 0.62 0.39
3880 SWM4217 0.0041 368 8 12 1,485 0.297 0.976 1.00 0.61 1.51 0.66
4792 SWM5195 0.0062 218 8 10 1,353 0.271 0.893 1.00 0.69 1.12 0.80
4793 SWM5196 0.0067 86 8 10 1,479 0.296 0.970 1.00 0.70 1.17 0.84
4890 SWM5293 0.0063 306 8 10 1,289 0.258 0.853 1.00 0.66 1.07 0.76
6453 SWM4206 0.0065 308 8 10 960 0.192 0.646 1.00 0.60 0.91 0.57
Chestnut, Roosevelt, Magnolia Improvement Group: Density Bonus Scenario HGL, No Improvements
Chestnut, Roosevelt, Magnolia Improvement Group: Density Bonus Scenario HGL, With Improvements
May 12, 2026 Item #13 Page 62 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-9
Chestnut, Roosevelt, Magnolia Improvement Group: Density Bonus Scenario Flows
Chestnut, Roosevelt, Magnolia Improvement Group: Density Bonus Scenario d/D, No Improvements
Chestnut, Roosevelt, Magnolia Improvement Group: Density Bonus Scenario d/D, With Improvements
May 12, 2026 Item #13 Page 63 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-10
Harding St & Grand Ave Improvement Group: Gravity Main IDs
May 12, 2026 Item #13 Page 64 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
May 12, 2026 Item #13 Page 65 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-12
Harding St & Grand Ave Improvement Group: Density Bonus Scenario Tabular Model Results
Model ID Facility ID Slope Length (ft)
Existing Diameter (in)
Upsized Diameter (in)
Tributary EDUs ADWF (mgd)PWWF (mgd)
d/D No Improve-ments
d/D With Improve-ments
q/Q No Improve-ments
q/Q With Improve-ments
3906 SWM4274 0.0271 350 6 8 269 0.054 0.299 0.75 0.66 0.50 0.23
4857 SWM5260 0.0281 65 12 15 2,554 0.511 1.583 0.35 0.26 0.41 0.23
4858 SWM5261 0.4936 17 12 15 2,820 0.564 1.672 0.61 0.58 0.10 0.06
4864 SWM5267 0.0121 380 10 15 2,152 0.430 1.426 0.68 0.37 0.91 0.31
6449 SWM4202 0.0164 280 8 10 1,163 0.233 0.867 1.00 0.68 0.86 0.48
6481 SWM4270 0.0023 241 10 12 1,306 0.261 0.953 1.00 0.72 1.40 0.87
6482 SWM4271 0.0029 242 10 12 1,420 0.284 1.017 1.00 0.64 1.33 0.83
6483 SWM4272 0.0038 239 10 15 1,684 0.337 1.083 1.00 0.53 1.23 0.42
6484 SWM4273 0.0014 240 10 15 1,744 0.349 1.096 1.00 0.61 2.04 0.70
6485 SWM4275 0.0028 490 10 15 2,096 0.419 1.413 0.89 0.50 1.87 0.64
6599 SWM6562 0.0332 199 6 8 200 0.040 0.145 0.41 0.27 0.22 0.10
Harding St & Grand Ave Improvement Group: Density Bonus Scenario HGL, No Improvements
Harding St & Grand Ave Improvement Group: Density Bonus Scenario HGL, With Improvements
May 12, 2026 Item #13 Page 66 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-13
Harding St & Grand Ave Improvement Group: Density Bonus Scenario Flows
Harding St & Grand Ave Improvement Group: Density Bonus Scenario d/D, No Improvements
Harding St & Grand Ave Improvement Group: Density Bonus Scenario d/D, With Improvements
May 12, 2026 Item #13 Page 67 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-14
Jefferson Street Improvement Group: Gravity Main IDs
May 12, 2026 Item #13 Page 68 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-15
Jefferson Street Improvement Group: Tributary Area
May 12, 2026 Item #13 Page 69 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-16
Jefferson Street Improvement Group: Density Bonus Scenario Tabular Model Results
Model ID Facility ID Slope Length (ft)
Existing Diameter (in)
Upsized Diameter (in)
Tributary EDUs ADWF (mgd)PWWF (mgd)
d/D No Improve-ments
d/D With Improve-ments
q/Q No Improve-ments
q/Q With Improve-ments
4870 SWM5273 0.0038 322 8 10 490 0.098 0.348 1.00 0.49 0.72 0.40
4871 SWM5274 0.0053 330 8 10 800 0.160 0.594 1.00 0.58 1.05 0.58
4872 SWM5275 0.0056 352 8 10 871 0.174 0.636 0.66 0.44 1.09 0.60
4873 SWM5276 0.0038 322 8 10 363 0.073 0.269 0.77 0.41 0.55 0.31
4867 SWM527 0.1631 42 12 12 1,349 0.270 0.939 0.21 0.21 0.10 0.10
Jefferson Street Improvement Group: Density Bonus Scenario HGL, No Improvements
Jefferson Street Improvement Group: Density Bonus Scenario HGL, With Improvements
May 12, 2026 Item #13 Page 70 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-17
Jefferson Street Improvement Group: Density Bonus Scenario Flows
Jefferson Street Improvement Group: Density Bonus Scenario d/D, No Improvements
Jefferson Street Improvement Group: Density Bonus Scenario d/D, With Improvements
May 12, 2026 Item #13 Page 71 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-18
Washington St Improvement Group: Gravity Main IDs
May 12, 2026 Item #13 Page 72 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TM
City of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-19
Washington St Improvement Group: Tributary Area
May 12, 2026 Item #13 Page 73 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-20
Washington St Improvement Group: Density Bonus Scenario Tabular Model Results
Model
ID
Facility
ID Slope
Length
(ft)
Existing
Diameter
(in)
Upsized
Diameter
(in)
Tributary
EDUs
ADWF
(mgd)
PWWF
(mgd)
d/D No
Improvements
d/D With
Improvements
q/Q No
Improvements
q/Q With
Improvements
6459 SWM4231 0.0035 319 8 10 263 0.053 0.660 1.00 0.65 1.24 0.79
6460 SWM4232 0.0036 350 8 10 278 0.056 0.618 0.92 0.62 1.11 0.73
6461 SWM4233 0.0039 349 8 10 288 0.058 0.569 0.78 0.54 1.01 0.64
6462 SWM4234 0.0064 355 8 10 308 0.062 0.544 0.84 0.61 0.78 0.48
3890 SWM4235 0.0017 347 8 10 332 0.066 0.482 0.87 0.62 1.56 0.82
3891 SWM4236 0.0041 345 8 10 348 0.070 0.437 0.65 0.47 0.83 0.48
4749 SWM5146 0.0020 245 10 12 690 0.138 0.652 0.78 0.56 0.97 0.63
4748 SWM5145 0.0027 190 10 12 754 0.151 0.685 0.95 0.45 0.90 0.57
4747 SWM5144 0.0159 351 10 12 913 0.183 0.774 1.00 0.53 0.41 0.27
3887 SWM4227 0.0028 351 10 15 1,796 0.359 1.361 1.00 0.58 1.51 0.62
3888 SWM4228 0.0028 366 10 15 1,943 0.389 1.435 1.00 0.59 1.61 0.65
200 SWM281 0.0028 241 10 15 2,002 0.400 1.469 1.00 0.58 1.66 0.67
201 SWM282 0.0035 241 10 15 2,036 0.407 1.489 0.74 0.46 1.49 0.60
Washington St Improvement Group: Density Bonus Scenario HGL, No Improvements
Washington St Improvement Group: Density Bonus Scenario HGL, With Improvements
May 12, 2026 Item #13 Page 74 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-21
Washington St Improvement Group: Density Bonus Scenario Flows
Washington St Improvement Group: Density Bonus Scenario d/D, No Improvements
Washington St Improvement Group: Density Bonus Scenario d/D, With Improvements
May 12, 2026 Item #13 Page 75 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-21
Washington St Improvement Group: Density Bonus Scenario Tabular Model Results
Model
ID
Facility
ID Slope
Length
(ft)
Existing
Diameter
(in)
Upsized
Diameter
(in)
Tributary
EDUs
ADWF
(mgd)
PWWF
(mgd)
d/D No
Improvements
d/D With
Improvements
q/Q No
Improvements
q/Q With
Improvements
6459 SWM4231 0.0035 319 8 10 263 0.053 0.660 1.00 0.65 1.24 0.79
6460 SWM4232 0.0036 350 8 10 278 0.056 0.618 0.92 0.62 1.11 0.73
6461 SWM4233 0.0039 349 8 10 288 0.058 0.569 0.78 0.54 1.01 0.64
6462 SWM4234 0.0064 355 8 10 308 0.062 0.544 0.84 0.61 0.78 0.48
3890 SWM4235 0.0017 347 8 10 332 0.066 0.482 0.87 0.62 1.56 0.82
3891 SWM4236 0.0041 345 8 10 348 0.070 0.437 0.65 0.47 0.83 0.48
4749 SWM5146 0.0020 245 10 12 690 0.138 0.652 0.78 0.56 0.97 0.63
4748 SWM5145 0.0027 190 10 12 754 0.151 0.685 0.95 0.45 0.90 0.57
4747 SWM5144 0.0159 351 10 12 913 0.183 0.774 1.00 0.53 0.41 0.27
3887 SWM4227 0.0028 351 10 15 1,796 0.359 1.361 1.00 0.58 1.51 0.62
3888 SWM4228 0.0028 366 10 15 1,943 0.389 1.435 1.00 0.59 1.61 0.65
200 SWM281 0.0028 241 10 15 2,002 0.400 1.469 1.00 0.58 1.66 0.67
201 SWM282 0.0035 241 10 15 2,036 0.407 1.489 0.74 0.46 1.49 0.60
Washington St Improvement Group: Density Bonus Scenario HGL, No Improvements
Washington St Improvement Group: Density Bonus Scenario HGL, With Improvements
May 12, 2026 Item #13 Page 76 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Village & Barrio Area Densification Collection System Modeling TMCity of Carlsbad Utilities Department, Engineering Division
Appendix A: Detailed Model Results
A-22
Washington St Improvement Group: Density Bonus Scenario Flows
Washington St Improvement Group: Density Bonus Scenario d/D, No Improvements
Washington St Improvement Group: Density Bonus Scenario d/D, With Improvements
May 12, 2026 Item #13 Page 77 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Engineer’s Report for Sewer Benefit Area N
APPENDIX B
SEWER BENEFIT AREA
BOUNDARY MAPS
May 12, 2026 Item #13 Page 78 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
LE
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May 12, 2026 Item #13 Page 79 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
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May 12, 2026 Item #13 Page 80 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Engineer’s Report for Sewer Benefit Area N
APPENDIX C
COST ESTIMATES
May 12, 2026 Item #13 Page 81 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Cost Summary
Sewer Benefit Area N - Density Bonus Scenario
April 2026
Carlsbad Village Station SWM68 285 18.5 16.2 17.4 4,944.8 15
SWM273 256 16.2 19.0 17.6 4,505.6 15
541 Depth1:17.5 4,011,485$
Chestnut, Roosevelt, Magnolia SWM4206 308 11.4 10.0 10.7 3,291.0 10
SWM5293 306 10.0 9.9 9.9 3,040.1 10
SWM283 304 9.9 6.4 8.1 2,474.6 10
SWM5195 218 6.4 6.2 6.3 1,371.2 10
SWM5196 86 6.2 6.8 6.5 556.0 10
SWM4217 368 6.8 9.3 8.0 2,949.5 12
SWM4216 368 9.3 15.7 12.5 4,596.3 12
SWM479 201 15.7 15.6 15.7 3,147.7 15
SWM462 341 15.6 12.6 14.1 4,803.0 15
SWM443 47 12.6 18.8 15.7 736.3 15
2,547 Depth1:10.6 4,012,201$
Harding St and Grand Ave SWM4202 280 7.2 9.2 8.2 2,294.6 10
SWM4270 241 9.2 10.0 9.6 2,317.2 12
SWM4271 242 10.0 7.1 8.6 2,077.6 12
SWM4272 239 7.1 10.6 8.8 2,112.8 15
SWM4273 240 10.6 8.0 9.3 2,226.0 15
SWM4275 490 8.0 11.6 9.8 4,806.9 15
SWM5267 380 11.6 10.4 11.0 4,174.3 15
SWM5260 65 10.4 11.2 10.8 699.4 15
SWM5261 17 11.2 18.8 15.0 254.5 15
SWM6562 199 4.3 6.6 5.4 1,076.6 8
SWM4274 350 6.6 8.0 7.3 2,546.3 8
2,743 Depth1:9.0 5,589,559$
Jefferson St SWM5276 322 9.3 8.8 9.1 2,920.5 10
SWM5273 322 8.8 8.0 8.4 2,709.6 10
SWM5274 330 8.0 8.0 8.0 2,641.7 10
SWM5275 352 8.0 8.8 8.4 2,948.0 10
SWM5270 42 8.8 15.1 11.9 500.6 12
1,368 Depth1:8.6 2,709,680$
Washington St SWM4231 319 8.5 10.0 9.2 2,949.2 10
SWM4232 350 10.0 8.8 9.4 3,288.3 10
SWM4233 349 8.8 10.1 9.4 3,289.3 10
SWM4234 355 10.1 5.2 7.6 2,706.9 10
SWM4235 347 5.2 10.0 7.6 2,637.2 10
SWM4236 345 10.0 15.5 12.7 4,395.3 10
SWM4227 351 17.1 11.0 14.0 4,929.8 15
SWM4228 366 11.0 16.2 13.6 4,979.4 15
SWM281 241 16.2 19.7 18.0 4,327.2 15
SWM282 241 19.7 22.4 21.1 5,079.1 15
3,264 Depth1:11.8 11,906,289$
Home Plant Lift Station SWGM101306 20 17.6 17.8 17.7 353.0 18
- -
20 Depth1:17.7 2,525,264$
1. Average depth, weighted for pipe length.
Total Cost, Density Bonus Scenario:30,754,478$
Total Cost
Avg.
Depth
(ft)
D/S
Depth
(ft)
Sewer Group Facility ID Length
(ft)
U/S
Depth
(ft)
Length x
Avg. Depth
(ft2)
Sewer Pipe
Diameter
(in)
C-1May 12, 2026 Item #13 Page 82 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Opinion of Probable Construction Cost
Sewer Group - Carlsbad Village Station
Item Description Unit Quantity Unit Price Item Cost
1 Mobilization not to exceed 10% LS 1 $149,000 $149,000
2 Traffic Control Plan Preparation & Implementation LS 1 $9,500 $9,500
3 Tier II SWPPP Preparation & Implementation LS 1 $4,000 $4,000
4 Excavation Support System LS 1 $16,000 $16,000
5 Utility Potholing and Locating LS 1 $8,000 $8,000
6 Sewer Bypass System LS 1 $96,500 $96,500
7 Groundwater Dewatering System Permits &
Implementation LS 1 $107,000 $107,000
8 Construct 15-Inch PVC Sewer LF 285 $804 $229,140
9 Construct 15-Inch PVC Sewer (Trenchless)LF 256 $3,600 $921,600
10 Modify and Rehabilitate Sewer Access Hole EA 3 $19,700 $59,100
11 Trench Resurfacing per Carlsbad Std. Dwg. GS-26 LF 285 $112 $31,920
12 Replace Street Markings and Striping In-kind LS 1 $4,000 $4,000
Subtotal:$1,635,760
30%Contingency:$490,728
Total Construction Cost:$2,126,488
Other Costs
13 Plans, Specifications & Estimates LS 1 $319,000 $319,000
14 Geotechnical Investigation LS 1 $86,000 $86,000
15 Environmental Studies LS 1 $43,000 $43,000
16 Cultural & Archaeological Resources Monitoring LF 541 $35 $18,935
17 Construction Management LS 1 $319,000 $319,000
18 Special Inspection Services LF 541 $70 $37,870
19 Public Outreach LS 1 $32,000 $32,000
20 City Improvement Plan Review LS 1 $63,000 $63,000
21 City Improvement Inspection LS 1 $47,000 $47,000
22 NCTD Permit Fees (one-time)LS 1 $39,140 $39,140
23 NCTD Permit Fees (recurring, present worth)LS 1 $880,052 $880,052
Subtotal:$1,884,997
Total Sewer Group - Carlsbad Village Station:$4,011,485
C-2May 12, 2026 Item #13 Page 83 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Opinion of Probable Construction Cost
Sewer Group - Chestnut Ave, Roosevelt St, Magnolia Ave
Item Description Unit Quantity Unit Price Item Cost
1 Mobilization not to exceed 10% LS 1 $189,000 $189,000
2 Traffic Control Plan Preparation & Implementation LS 1 $51,800 $51,800
3 Tier II SWPPP Preparation & Implementation LS 1 $22,000 $22,000
4 Excavation Support System LS 1 $57,500 $57,500
5 Utility Potholing and Locating LS 1 $44,000 $44,000
6 Sewer Bypass System LS 1 $164,800 $164,800
7 Groundwater Dewatering System Permits &
Implementation LS 1 $182,000 $182,000
8 Construct 10-Inch PVC Sewer LF 244 $500 $122,000
9 Construct 12-Inch PVC Sewer LF 736 $550 $404,800
10 Construct 15-Inch PVC Sewer LF 589 $621 $365,769
11 Modify and Rehabilitate Sewer Access Hole EA 14 $19,700 $275,800
12 Trench Resurfacing per Carlsbad Std. Dwg. GS-26 LF 1,569 $112 $175,728
13 Replace Street Markings and Striping In-kind LS 1 $19,000 $19,000
Subtotal:$2,074,197
30%Contingency:$622,259
Total Construction Cost:$2,696,456
Other Costs
14 Plans, Specifications & Estimates LS 1 $405,000 $405,000
15 Geotechnical Investigation LS 1 $108,000 $108,000
16 Environmental Studies LS 1 $54,000 $54,000
17 Cultural & Archaeological Resources Monitoring LF 1,569 $35 $54,915
18 Construction Management LS 1 $405,000 $405,000
19 Special Inspection Services LF 1,569 $70 $109,830
20 Public Outreach LS 1 $41,000 $41,000
21 City Improvement Plan Review LS 1 $79,000 $79,000
22 City Improvement Inspection LS 1 $59,000 $59,000
Subtotal:$1,315,745
Total Sewer Group - Chestnut Ave, Roosevelt St, Magnolia Ave:$4,012,201
C-3May 12, 2026 Item #13 Page 84 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Opinion of Probable Construction Cost
Sewer Group - Harding St, Grand Ave
Item Description Unit Quantity Unit Price Item Cost
1 Mobilization not to exceed 10% LS 1 $260,000 $260,000
2 Traffic Control Plan Preparation & Implementation LS 1 $90,600 $90,600
3 Tier II SWPPP Preparation & Implementation LS 1 $38,500 $38,500
4 Excavation Support System LS 1 $87,800 $87,800
5 Utility Potholing and Locating LS 1 $76,900 $76,900
6 Sewer Bypass System LS 1 $160,000 $160,000
7 Groundwater Dewatering System Permits &
Implementation LS 1 $176,000 $176,000
8 Construct 8-Inch PVC Sewer LF 549 $407 $223,443
9 Construct 10-Inch PVC Sewer LF 280 $450 $126,000
10 Construct 12-Inch PVC Sewer LF 483 $496 $239,568
11 Construct 15-Inch PVC Sewer LF 1,431 $562 $804,222
12 Modify and Rehabilitate Sewer Access Hole EA 12 $19,700 $236,400
13 Trench Resurfacing per Carlsbad Std. Dwg. GS-26 LF 2,743 $112 $307,216
14 Replace Street Markings and Striping In-kind LS 1 $33,000 $33,000
Subtotal:$2,859,649
30%Contingency:$857,895
Total Construction Cost:$3,717,544
Other Costs
15 Plans, Specifications & Estimates LS 1 $558,000 $558,000
16 Geotechnical Investigation LS 1 $149,000 $149,000
17 Environmental Studies LS 1 $75,000 $75,000
18 Cultural & Archaeological Resources Monitoring LF 2,743 $35 $96,005
19 Construction Management LS 1 $558,000 $558,000
20 Special Inspection Services LF 2,743 $70 $192,010
21 Public Outreach LS 1 $56,000 $56,000
22 City Improvement Plan Review LS 1 $108,000 $108,000
23 City Improvement Inspection LS 1 $80,000 $80,000
Subtotal:$1,872,015
Total Sewer Group - Harding St, Grand Ave:$5,589,559
C-4May 12, 2026 Item #13 Page 85 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Opinion of Probable Construction Cost
Sewer Group - Jefferson St
Item Description Unit Quantity Unit Price Item Cost
1 Mobilization not to exceed 10% LS 1 $126,000 $126,000
2 Traffic Control Plan Preparation & Implementation LS 1 $44,000 $44,000
3 Tier II SWPPP Preparation & Implementation LS 1 $19,000 $19,000
4 Excavation Support System LS 1 $44,000 $44,000
5 Utility Potholing and Locating LS 1 $38,000 $38,000
6 Sewer Bypass System LS 1 $101,000 $101,000
7 Groundwater Dewatering System Permits &
Implementation LS 1 $112,000 $112,000
8 Construct 10-Inch PVC Sewer LF 1,326 $450 $596,700
9 Construct 12-Inch PVC Sewer LF 42 $496 $20,832
10 Modify and Rehabilitate Sewer Access Hole EA 6 $19,700 $118,200
11 Trench Resurfacing per Carlsbad Std. Dwg. GS-26 LF 1,368 $107 $146,376
12 Replace Street Markings and Striping In-kind LS 1 $17,000 $17,000
Subtotal:$1,383,108
30%Contingency:$414,932
Total Construction Cost:$1,798,040
Other Costs
13 Plans, Specifications & Estimates LS 1 $270,000 $270,000
14 Geotechnical Investigation LS 1 $72,000 $72,000
15 Environmental Studies LS 1 $36,000 $36,000
16 Cultural & Archaeological Resources Monitoring LF 1,368 $35 $47,880
17 Construction Management & Inspection LS 1 $270,000 $270,000
18 Special Inspection Services LF 1,368 $70 $95,760
19 Public Outreach LS 1 $27,000 $27,000
20 City Improvement Plan Review LS 1 $53,000 $53,000
21 City Improvement Inspection LS 1 $40,000 $40,000
Subtotal:$911,640
Total Sewer Group - Jefferson St:$2,709,680
C-5May 12, 2026 Item #13 Page 86 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Opinion of Probable Construction Cost
Sewer Group - Washington St
Item Description Unit Quantity Unit Price Item Cost
1 Mobilization not to exceed 10% LS 1 $373,000 $373,000
2 Traffic Control Plan Preparation & Implementation LS 1 $90,000 $90,000
3 Tier II SWPPP Preparation & Implementation LS 1 $39,000 $39,000
4 Excavation Support System LS 1 $115,000 $115,000
5 Utility Potholing and Locating LS 1 $77,000 $77,000
6 Sewer Bypass System LS 1 $179,000 $179,000
7 Groundwater Dewatering System Permits &
Implementation LS 1 $197,000 $197,000
8 Construct 10-Inch PVC Sewer LF 2,065 $550 $1,135,750
9 Construct 12-Inch PVC Sewer LF 786 $604 $474,744
10 Construct 15-Inch PVC Sewer LF 1,199 $681 $816,519
11 Modify and Rehabilitate Sewer Access Hole EA 14 $19,700 $275,800
12 Trench Resurfacing per Carlsbad Std. Dwg. GS-26 LF 2,720 $109 $296,480
13 Replace Street Markings and Striping In-kind LS 1 $33,000 $33,000
Subtotal:$4,102,293
30%Contingency:$1,230,688
Total Construction Cost:$5,332,981
Other Costs
14 Plans, Specifications & Estimates LS 1 $800,000 $800,000
15 Geotechnical Investigation LS 1 $214,000 $214,000
16 Environmental Studies LS 1 $107,000 $107,000
17 Cultural & Archaeological Resources Monitoring LF 4,050 $35 $141,750
18 Construction Management LS 1 $800,000 $800,000
19 Special Inspection Services LF 4,050 $70 $283,500
20 Public Outreach LS 1 $80,000 $80,000
21 City Improvement Plan Review LS 1 $145,000 $145,000
22 City Improvement Inspection LS 1 $108,000 $108,000
23 NCTD Permit Fees (one-time)LS 1 $52,580 $52,580
24 NCTD Permit Fees (recurring, present worth)LS 1 $3,841,478 $3,841,478
Subtotal:$6,573,308
Total Sewer Group - Washington St:$11,906,289
C-6May 12, 2026 Item #13 Page 87 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55
Opinion of Probable Construction Cost
Sewer Group - Home Plant
Item Description Unit Quantity Unit Price Item Cost
1 Mobilization not to exceed 10% LS 1 $122,000 $122,000
2 Traffic Control Plan Preparation & Implementation LS 1 $1,000 $1,000
3 Tier II SWPPP Preparation & Implementation LS 1 $14,000 $14,000
4 Excavation Support System LS 1 $150,000 $150,000
5 Utility Potholing and Locating LS 1 $6,000 $6,000
6 Sewer Bypass System LS 1 $130,000 $130,000
7 Groundwater Dewatering System Permits &
Implementation LS 1 $143,000 $143,000
8 Construct 18-Inch PVC Sewer LF 20 $1,470 $29,400
9 Modify and Rehabilitate Sewer Access Hole EA 1 $19,700 $19,700
10 Construct Wet Well Enlargement LS 1 $635,000 $635,000
11 Knife Gate - Stainless Steel EA 2 $40,000 $80,000
12 Trench Resurfacing per Carlsbad Std. Dwg. GS-26 LF 30 $106 $3,180
13 Replace Street Markings and Striping In-kind LS 0 $0 $0
Subtotal:$1,333,280
30%Contingency:$399,984
Total Construction Cost:$1,733,264
Other Costs
14 Plans, Specifications & Estimates LS 1 $260,000 $260,000
15 Geotechnical Investigation LS 1 $70,000 $70,000
16 Environmental Studies LS 1 $35,000 $35,000
17 Cultural & Archaeological Resources Monitoring LS 1 $15,000 $15,000
18 Construction Management & Inspection LS 1 $260,000 $260,000
19 Special Inspection Services LS 1 $35,000 $35,000
20 Public Outreach LS 1 $26,000 $26,000
21 City Improvement Plan Review LS 1 $52,000 $52,000
22 City Improvement Inspection LS 1 $39,000 $39,000
Subtotal:$792,000
Total Sewer Group - Home Plant:$2,525,264
C-7May 12, 2026 Item #13 Page 88 of 89
Docusign Envelope ID: D5021F52-70FB-43E8-A859-81DC26CB1E55