OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted to our care.
525 Golden Gate Avenue, 13th Floor
San Francisco, CA 94102
T 415.554.3155
F 415.554.3161
TTY 415.554.3488
June 12, 2025
To: Commissioner Kate H. Stacy, President
Commissioner Joshua Arce, Vice President
Commissioner Avni Jamdar
Commissioner Stephen E. Leveroni
Commissioner Meghan Thurlow
Through: Dennis J. Herrera, General Manager
From: Steven R. Ritchie, Assistant General Manager, Water Paula Kehoe, Manager, Water Resources Division
Subject: Alternative Water Supply Annual Progress Report
Enclosed please find the Annual Progress Report for the Alternative Water Supply (AWS) Program, which provides an update of the progress made from July 2024 to May 2025 on the status of new regional water supply projects that are being planned within the SFPUC’s service area to meet future water supply challenges and vulnerabilities such as offsetting environmental flow requirements and regulatory changes; changes in demand; and climate change. This is the second annual progress report since the AWS Plan was published in February 2024.
This report is organized in three sections. Section 1 introduces the AWS Program and is not intended to fully summarize the AWS Plan but provide sufficient context about the program to support the information in Sections 2 and 3. Section 2 provides an update on the recommendations that were included in the AWS Plan, a financial update, and programmatic updates.
Lastly, Section 3 describes project-specific updates for the reporting year, including achievements on AWS projects, financial expenditures, and planned future activities.
cc: Tom Smegal, BAWSCA
Tom Francis, BAWSCA
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
1 SAN FRANCISCO PUBLIC UTILITIES COMMISSION
ALTERNATIVE WATER SUPPLY
ANNUAL PROGRESS REPORT
2024-2025
San Andreas Reservoir, 2022
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
2 Table of Contents
Report Overview and Organization 3
Section 1: AWS Program and Plan Background 4
1.1 Water Supply Availability 4
1.2 SFPUC Obligations and Demands 5
1.3 The Water Supply Gap 6
1.4 AWS Projects & Recommendations 8
1.5 Local Water Supply Projects 10
1.6 San Joaquin Valley & Upcountry Projects 13
Section 2: Program Highlights and Updates 14
2.1 Progress on AWS Plan Recommendations 14
2.2 Financial Update 17
2.3 Programmatic Updates 18
2.3.1 Negotiations Related to the Agreements to Support Healthy Rivers and Landscapes 18
2.3.2 Consideration of Permanent Status with San Jose and Santa Clara 18
2.3.3 Future Demand Scenarios 19
2.3.4 Staffing Support 20
2.3.5 Supporting Demand Reduction on the Regional Water System 20 Section 3: Update on AWS Projects 22
3.1 Active Projects 22
3.1.1 PureWater Peninsula 24
3.1.2 South Bay Purified Water 27
3.2 Potential Projects (including Deferred Projects) 30
3.2.1 Regional Conveyance Alternatives 31
3.2.2 Regional Supply Alternatives 34
3.2.3 Daly City Recycled Water 36
3.2.4 ACWD-USD Purified Water 37
3.2.5 Calaveras Reservoir Expansion 38
3.3 Canceled Project 39
3.3.1 Los Vaqueros Reservoir Expansion 40
3.4 Looking Ahead 41
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
3 Report Overview and Organization
This 2024-2025 Annual Progress Report provides a status update on the Alternative Water Supply (AWS) Program.
In February 2024, the San Francisco Public Utilities Commission (SFPUC) published the AWS Plan, a roadmap for the AWS Program and primary reference document for planning related to new dry year water supply projects. Until any significant updates are made to the AWS Plan or its assumptions, progress reports provide annual updates on programmatic priorities and projects related to the AWS Program. Therefore, this progress report serves as a companion to the 2024 AWS Plan.
This report is organized in three sections.
Section 1 (AWS Program and Plan Background) provides a brief introduction to the AWS Program.
This section is not intended to fully summarize the AWS Plan, but rather provide sufficient context about the program to support the information presented in Sections 2 and 3. For a more complete description of the AWS Program guidance and priorities, readers are encouraged to review the AWS Plan in its entirety, which can be found online at www.sfpuc.gov/awsplan.
Section 2 (Program Highlights and Updates) provides AWS programmatic and financial updates for the period between July 202 4 and May 2025. This section also identifies progress made on the recommendations that were included in the AWS Plan.
Section 3 (Update on AWS Projects) provides project-specific updates within the AWS Program. This section is split into active projects that the SFPUC is planning for and inactive projects that are currently deferred or canceled.
San Andreas Reservoir, 2024
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
4 Section 1: AWS Program and Plan Background
In 2019, the San Francisco Public Utilities Commission (SFPUC) established the Alternative Water Supply (AWS) Program to identify and plan water supply and storage projects and actions that increase the dry-year reliability of Regional Water System (RWS). Based on a 2045 planning horizon, the SFPUC anticipates a water supply gap in future dry years. The AWS Program is designed to help fill this gap by supplementing demand management actions and ongoing developments of local and regional capital projects.
The AWS Plan, published in February 2024, is the main reference document for the AWS Program and includes:
Calculation of and context for the projected water supply gap in the 2045 planning horizon Description of ongoing efforts to reduce demands and optimize supply availability Details of AWS Projects that can augment RWS supply and address the future water supply gap
Recommendations that will further advance the AWS Program and its objectives This section includes some of the key elements of the AWS Plan. Any updates that have occurred since the publication of the AWS Plan are explicitly noted as such in this document.
1.1 Water Supply Availability
The SFPUC’s water supply planning methodology for dry -year conditions estimates the total system yield (or water availability), which includes direct water supply from the Regional Water System and Water System Improvement Program (WSIP) projects and the estimated rationing that would address a portion of demands during droughts. While there are several drivers that may limit water supply in the future, instream flow requirements associated with the State Water Resources Control Board’s San Francisco Bay/Sacramento-San Joaquin Delta Estuary Water Quality Control Plan as amended in 2018 (Bay-Delta Plan Amendment) could have the most pronounced impact on water availability for the 2045 planning horizon.
Calaveras Reservoir, 2024
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
5 The Bay-Delta Plan Amendment, if implemented as adopted by the State in 2018, would result in new instream flow requirements that would significantly reduce the SFPUC’s available water supply.
These new instream flow requirements result in a projected water availability in dry years (expressed as total system yield) of 152 mgd, see Table 1.
Table 1. Projected 2045 Water Availability during Dry Years with the Bay-Delta Plan Amendment
Scenario with Bay-
Delta Plan Amendment
Baseline Water Supply with WSIP Implemented 227
New Instream Flow Release Requirements from
the Bay-Delta Plan Amendment -93
Water Supplya (Firm Yield) 134
Demands Addressed through Implementation of
Rationing Policyb 18
Water Availability (Total System Yield)c 152
a Firm yield includes implemented WSIP Projects, current instream flow releases, and 93 mgd of additional instream flow releases associated with implementation of the Bay-Delta Plan Amendment.
b The water supply benefit realized through rationing is proportional to the available water supply (firm yield). Because the instream flow requirements called for in the Bay-Delta Plan Amendment would reduce the firm yield, the supply benefit realized through rationing is also reduced. c Total system yield is the sum of system firm yield plus the water demand addressed through rationing during extended drought.
1.2 SFPUC Obligations and Demands
The SFPUC has a legal and contractual obligation to deliver up to 184 mgd annually (Supply Assurance) to 24 of the 26 wholesale customers represented by the Bay Area Water Supply and Conservation Agency (BAWSCA). The Water Supply Agreement between the SFPUC and its customers carries forward the Supply Assurance, which is perpetual and survives the expiration of the agreement. Customers who are included in the Supply Assurance are referred to as Wholesale Customers. San Jose and Santa Clara are the two customers who are provided water on an interruptible basis.
San Jose and Sant a Clara have received deliveries from the SFPUC continuously since the 1970s.
Based on their historical purchases, the AWS Program includes 9 mgd as both a projected demand and potential future obligation for San Jose and Santa Clara, enabling the Commission to understand the future total obligations if it were to make this commitment in the future. In accordance with the Water Supply Agreement, the Commission will have to make a policy decision by December 31, 2028 on whether to provide a permanent water supply to the two cities.
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
6 In addition to wholesale obligations, the SFPUC provides an allocation of up to 81 mgd (Retail Allocation) to customers in San Francisco and suburban retail customers ( Retail Customers). The combined Supply Assurance and Retail Allocation (265 mgd) along with the consideration to make San Jose and Santa Clara permanent customers (9 mgd) are current and potential future obligation drivers that affect the magnitude of the future water supply gap.
Customer projected demands for 2045 reflected in the AWS Plan were from the SFPUC 2020 Urban Water Management Plan, adjusted for changes to the Non-Potable Ordinance in 2021 (retail demand) and the FY 2021 -2022 BAWSCA Annual Survey ( wholesale demand). Since then, the SFPUC has released the 2023 Interim Water Demand Projections Update due to new housing unit projections from the certified Housing Element 2022 Update which projects slightly higher multi -family housing units than those used in the 2020 Urban W ater Management Plan. Additionally, BAWSCA has published its FY 202 3-24 Annual Survey (April 2025) which includes minor updates to the 2045 demand projections since the AWS Plan was published . While AWS staff will continue to track the small interim changes to the demand projections, no changes are being made to the water supply gap calculation from the AWS Plan until planned demand projections are completed in preparation for the 2025 Urban Water Management Plan and 1 -2 additional demand scenarios are deve loped, as recommended in the AWS Plan.
1.3 The Water Supply Gap
The anticipated water supply gap is characterized as the difference between water availability and a) existing and potential future obligations or b) estimated future customer demands. Figure 1 shows the future water supply gap for meeting obligations and 2045 demands in dry -year conditions, as described in the AWS Plan. The future water supply gap is characterized as a range of 92 mgd to meet 2045 customer demands to 122 mgd to meet obligations.
Changes to either water availability or 2045 demand projections can result in changes to the water supply gap. On the supply side, negotiations with the State are ongoing regarding implementation of the Bay -Delta Plan Amendment . On the demand side, the SFPUC is updating its retail demand projections in preparation for the 2025 Urban Water Management Plan and developing 1 -2 new demand scenarios in response to the AWS Plan recommendations. Furthermore, BAWSCA is updating regional demand projections and preparing its Strategy 2050, a regional planning study. The next significant update to the AWS Plan contemplates these activities and therefore is scheduled to be prepared in 2027.
To avoid overbuilding new water supply projects, the approach reflected in the AWS Program is to Plan for Obligations and Build for Demands.
This approach recognizes the importance of contemplating water supplies to meet obligations while prioritizing investments that focus on the most imminent need of meeting customer demands. As projected demands are lower than current and potential obligations, investment recommendations will continue to focus on the gap between demands and estimated supply availability.
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
7 Meanwhile, water supply gap c alculation assumptions from the 2024 AWS Plan remain . If the Bay - Delta Plan Amendment is implemented as adopted in 2018, the SFPUC could immediately experience a water supply shortfall and be unable to meet customer demands in dry years. While the AWS Plan uses a planning horizon of year 2045 to allow time for projects and other actions to be developed , impacts to water supply could occur much sooner and create an urgency to address the projected water supply gap. However, early investigation of ways to close the water supply gap with dry-year water supply projects or demand reduction actions indicate that opportunities are very limited, often requiring complex multi-party partnerships.
Beside water supply projects and other actions that would reduce demands on the Regional Water System, the AWS Program also a nticipates that rationing could contribute to filling up to 12% of the water supply gap. The volume of demands that rationing can address is dependent on water supply.
If estimated new water supplies to fill the future water supply gap are less than what is needed, the estimated contribution of rationing would also be proportionately less. Figure 2 illustrates how rationing and new alternative water supplies work together to address the water supply gap.
Figure 1. Anticipated Water Supply Gap (as of February 2024)
a Represents the total system yield. The total system yield is the sum of the firm yield of the RWS plus rationing (134 mgd firm yield and 18 mgd of demands addressed by implementing the rationing policy).
b The water supply gap estimates: 1) the total difference between water availability and obligations and 2) the difference between water availability and customer demands on the RWS in 2045.
c As rationing is a function of water supply availability, to close the gap with new supplies and rationing, new supplies of 107 mgd would be required. Up to 15 mgd of the water supply gap can then be met by rationing.
d As rationing is a function of water supply availability, to close the gap with new supplies and rationing, new supplies of 81 mgd would be required. Up to 11 mgd of the water supply gap can then be met with rationing.
152 mgd
(assumes implementation of the Bay-Delta Plan Amendment) Water Availability through the RWSa
265 mgd
(existing Retail and Wholesale)
+ 9 mgd
(San Jose and Santa Clara)
Total Existing and
Potential Obligations
244 mgd
(including Retail, Wholesale,
San Jose, and Santa Clara)
Total 2045 Demands
on the RWS
-122 mgdc
(to meet obligations)
Water Supply Gapb
-92 mgdd
(to meet 2045 demands)
Water Supply Gapb
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
8 1.4 AWS Projects & Recommendations
The AWS Plan included six AWS Projects to partially address the projected 2045 water supply gap. The AWS Projects
include two storage expansion projects with associated
conveyance (and supply, if needed) , one recycled water project that increases the availability of potable groundwater in dry years, and three purified water projects that would provide a new source of supply, including in dry years. Based on 2024 planning estimates, these projects were expected to augment supplies from 19.5 mgd to 48 mgd in future dry years. Increases in supply would also result in additional benefits from corresponding increases in rationing.
The significant range from 19.5 mgd to 48 mgd re flected the uncertainty related to the expansion of Calaveras Reservoir. As explained in Section 2, funding for the further development of this project had been deferred in the SFPUC’s capital plan concurrent with the publication of the AWS Plan. Thus, while the AWS Plan recognize d the Calaveras Reservoir Expansion could supply up to 28.6 mgd, funding for planning and implementation for projects was based on a maximum dry year yield of approximately 19.5 mgd in 2024. It is important to note that even those projects described in the AWS Plan were in the planning phase and continued to carry feasibility risks that have since further reduced the dry year supply potential . As described further in this report, even with additional rationing the active AWS Projects would total less than 12 mgd, addressing only approximately 13% of the projected 2045 water supply gap based on current assumptions. While some planning assumptions are likely to change by 2027, it is still prudent to p ursue the current roster of AWS Projects that will provide local dry year supplies that will diversify regional supplies and increase reliability for SFPUC customers.
Figure 2. SFPUC’s Planned Investment to Fill the Projected Water Supply Gap
In addition to the six AWS Plan
projects, t he SFPUC continues to
evaluate a wide range of water
supply sources from small,
community-based applications to
large-scale groundwater banking
in our upcountry watershed. These
efforts are grouped as either Local
Water Supply Projects or San
Joaquin Valle y & Upcountry
Projects in the following pages.
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
9 The AWS Plan recommendations were based on a need to
approach the water supply gap through three categories of actions: 1) avoid widening the gap by continued support for projects that are already being implemented; 2) fill the water supply gap with new dr ought-resistant supplies; and 3) encourage demand reduction or supply management actions that result in a smaller gap. Because no single approach will provide a solution, the SFPUC is focused on making progress toward each of these three objectives as it continues to implement the AWS Program. Section 2 discusses the
progress made on the three key objectives.
Yosemite National Park, 2024
Fill the
water
supply gap
Reduce the
water supply
gap
Avoid
widening
the water
supply gap
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
10 1.5 Local Water Supply Projects
The SFPUC implements new projects and initiative s in its retail service area that can offset future retail purchases from the RWS , thereby helping to reduce the water supply gap . Th ese projects supplement the SFPUC’s robust efforts in conservation, non -potable water reuse (both centralized and decentralized), and local and regional groundwater that have been underway for many years. The SFPUC has implemented conservation programs to minimize both indoor and outdoor retail water demands, resulting in an average residential indoor and outdoor water consumption rate of 40 gallons per person per day.1
The San Francisco Groundwater Supply Project has been underway to provide 4 mgd of local supply before 2045. However, to fully realize this water supply benefit, new treatment will be required to address organic compounds that were detected at three locations. Funding of $13.5 million was allocated in the FY25-34 CIP. Planning for the treatment project is underway.
PureWaterSF is a project that envisions providing a new, local drinking water supply in San Francisco by treating recycled water from the Oceanside and Southeast
Treatment Plants. In 2020, the SFPUC successfully
completed a small- scale research and demonstration
purified water project at its headquarters. With limited opportunities for large non-potable applications remaining in San Francisco, the SFPUC has evaluated the maximum
potential for recycling water for drinking or producing purified water that can be blended in San Francisco's
drinking water reservoirs consistent with draft regulations that were being developed by the State Water Resources
Control Board at the time. As of 2024, the regulations have been adopted and taken effect.
This fiscal year, the SFPUC applied findings from internal focus groups conducted in the summer of 2023 to co ntinue developing an outreach and public engagement plan and to initiate work on a citywide public opinion survey to be conducted in the summer of 2025 . In conjunction with new regulations and coordination with peer utilities throughout California, staff initiated a PureWaterSF Implementation Plan this year, the development of which will be an iterative and collaborative intra- agency process to ensur e that a ll project stakeholders are aligned, and that the project will be successfully permitted and operated from the demonstration phase through full-scale operation.
1 SFPUC Water Resources 2023-24 Annual Report
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
11 In additional to outreach and knowledge sharing, the SFPUC has also made headway in capital and facility
planning. The SFPUC property at 1990 Newcomb
Avenue, the current site of the San Francisco Water
Division (formerly known as the City Distribution
Division) offices and yard, is planned as the future home of a demonstration, training, and outreach facility as
well as PureWaterSF East Phase 1, a 2.5-mgd full-scale
facility serving the east side of San Francisco.
Identification of a similar site on the west side of San Francisco for PureWaterSF West is ongoing.
The Water Resources Division’s Innovations Program encourages testing of forward-thinking ideas.
The SFPUC partners with the community, industry, developers, technology vendors, and others who play key roles in ensuring the long -term sustainability of San Francisco. Water Innovation fits in with the SFPUC’s OneWaterSF approach. Included in the Innovations Program are the development of new technologies and initiatives to demonstrate the fea sibility of atmospheric water generation technology, wastewater heat recovery in onsite non-potable systems, expanded leak detection, and breweries treating process water for reuse. The SFPUC is also focused on developing new projects and opportunities for partnerships.
San Francisco’s Non-potable Water Ordinance allows for the collection, treatment, and use of alternate water sources for non-potable applications in individual buildings and at the district-scale.
The ordinance requires new developments of 100,000 square feet or more to install and operate an onsite water reuse system. The required alternate water sources and required non-potable uses are based on development project type (e.g. commercial vs. residential). Additionally, the SFPUC has an Onsite Water Reuse G rant Program f or projects that are installing an o nsite water system on a voluntary basis, projects that go above and beyond the Baseline Non-potable Ordinance, or projects that are installing onsite treatment and reuse of brewery process water.
This year, the SFPUC awarded a grant to a new
development project at 555 Bryant Street that is
installing a graywater treatment system to meet
non-potable water demands for toilet flushing,
irrigation, and clothes washing. As part of the
grant, the project is also installing the City’s first
wastewater heat recovery system, which will
reduce the energy consum ption of the onsite
water treatment system by using the extracted
thermal energy to pre -heat the potable water
supplied to the building’s water heater.
Photo from Solomon Cordwell Buenz
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
12 Stormwater Capture & Reuse focuses on the collection and harvest of stormwater and rainwater for reuse. Many properties that fall under the SFPUC city-wide mandates for new construction , which aim to manage stormwater runoff prior to discharge to the City storm system, utilize the ‘capture and reuse’ of stormwater and rainwater . Enacted in 2010, the Stormwater Management Ordinance requires new and redevelopment projects to manage stormwater runoff using green infrastructure , including rainwater collection and reuse, and to maintain that green infrastructure for the lifetime of the project. The SFPUC’s Stormwater Management Program provides guidance on how to incorporate green infrastructure into the site’s design.
Additionally, the Urban Watershed Management Division administers incentive -based grant programs to reduce stormwater runoff. Some of these grant programs include the Green Infrastructure Grant Program, Green Infrastructure Grants for Homes Program, Floodwater Management Grant Program, and Urban Watershed Stewardship Grant Program. Since the launch of the Green Infrastructure Grant Program in February 2019, the SFPUC has awarded $26.5 million in grants to 26 projects. When completed, the projects are design ed to capture and divert about 1 6 million gallons of stormwater per year. The program has continued to see a steady level of interest, with an average of four new projects awarded and $4.5 million in investments per year since the program’s inception. The program funded new projects to transform local outdoor spaces, reduce flood risk, improve urban habitat, increase climate resilience, and improve coastal water quality.
Under the Vista Grande Drainage Basin Improvement Project, the SFPUC is coordinating with the City of Daly City to divert stormwater from the Vista Grande Watershed to South Lake Merced. The project is aimed toward improving stormwater management, increasing lake levels, improve lake water quality, and restoring the Lake Merced Drainage Basin’s natural hydrology.
St. Anne of the Sunset School and Church, 2025
Green Infrastructure Grant Recipient
Section 1 – AWS Program and Plan Background
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
13 1.6 San Joaquin Valley & Upcountry Projects
In addition to projects that are being implemented locally and regionally in the San Francisco Bay Area, the SFPUC is also exploring projects that would extend the availability of existing surface water supplies from the Tuolumne River watershed under dry-year conditions. The following three projects are described in the AWS Plan and will continue to be updated as more information become available.
Groundwater Banking in the Modesto Irrigation District and Turlock Irrigation District service areas could be used to provide some additional water supply to meet instream releases in dry years reducing water supply impacts to the SFPUC service area. For example, additional surface water could be provided to irrigators in wet years, which would offset the use of groundwater, thereby allowing the groundwater to remain in the basin rather than be consumptively used. The groundwater that remains in the basin can then be used in a subsequent dry year for irrigation, freeing up surface water that would have otherwise been delivered to irrigators to meet instream flow requirements.
Feasibility study of this option is included in the Agreements to Support Healthy Rivers and Landscapes (previously referred to as the Tuolumne River Voluntary Agreement). Progress on this potential water supply option will be guided by scientific monitoring and collaborative decision making.
Inter-Basin Collaborations could include establishing a partnership between interests on the Tuolumne River and those on the Stanislaus River, which would allow responsibility for streamflow to be assigned variably based on the annual hydrology. The Tuolumne system tends to spill more excess flow in wetter years than the Stanislaus, and this excess flow could be shaped and credited to meet Stanislaus system requirements, while New Melones Reservoir in the Stanislaus system is refilling.
Then the stored water could be partially used to provide required streamflow to meet Stanislaus and Tuolumne requirements in future dry years.
Dry-Year Transfers have long been pursued by the SFPUC. During the planning and implementation of the Phased Water System Improvement Program, the SFPUC pursued a long -term agreement to transfer 2 mgd from Modesto Irrigation District in dry years only. The negotiations were terminated in 2012. Subsequently, the SFPUC initiated some discussions with Oakdale Irrigation District to secure a similar dry year transfer. While no transfer has been secured to date, the SFPUC continues to engage in discussions with partners to explore potential transfer opportunities on the Tuolumne River and throughout the San Joaquin Valley.
Moccasin Reservoir, 2024
Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
14 Section 2: Program Highlights and Updates
Section 2 presents the AWS program’s accomplishments and key milestones achieved throughout the 2024-2025 reporting period and the anticipated next steps.
2.1 Progress on AWS Plan Recommendations
The AWS Plan recognizes the potential for a significant future water supply gap and has identified recommendations that aim to (1) avoid widening the water supply gap, (2) fill the water supply gap, and (3) reduce the water supply gap. Table 2 lists the 15 recommendations outlined in Chapter 6 of the AWS Plan along with a status update.
Table 2. Current State of Each AWS Plan Recommendation
Recommendation Current Status
1. Support funding in the FY 2025-2034 CIP to evaluate alternatives for additional treatment, infrastructure, and associated staffing needed to achieve 6.2 mgd of dry-year supply by 2045 from the Regional Groundwater Storage and Recovery project. Staffing needs will be re-evaluated in a future CIP development process.
Funding approved,
evaluation of
alternatives will
begin once funding is
released in the
coming months.
2. Include the Phase 2 re-design of the Alameda Creek Recapture Project as a new project in the FY 2025-2034 CIP.
Funding approved,
the re-design effort
will begin once
funding is released in
the coming months.
Pilarcitos Reservoir, 2024
Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
15 Recommendation Current Status
3. Continue reporting progress on negotiations related to the Proposed Voluntary Agreement [now referred to as Agreements to Support Healthy Rivers and Landscapes] and potential transfers and projects in the San Joaquin Valley that could contribute to instream flow releases. Identify resource and funding needs, as and when appropriate. No new funding or additional resources are needed to support this recommendation.
Update anticipated in
FY 2025-2026. See
Section 2.3.1.
4. Provide updates to the AWS Plan, beginning in FY 2026-2027 and periodically thereafter, to align with AWS Project milestones, changes to regulatory requirements, and CIP planning. No new funding or resource allocation for this effort is anticipated.
Update to the AWS
Plan will be prepared
in FY 2026-2027.
5. Based on its assessment in 2024, the SFPUC will develop 1-2 additional demand scenarios for the retail service area including a sensitivity analysis as appropriate to understand the key inputs driving changes in demand. Past projections should be compared to actual deliveries to calibrate the new demand scenario(s). Staff should also collaborate closely with BAWSCA in this effort to track retail and wholesale assumptions
Demand scenarios
are currently being
evaluated and
expected to be
completed by early
2026. See Section
2.3.3. 6. Evaluate infrastructure and operational needs and estimate any additional funding necessary to achieve 4 mgd of dry-year supply by 2045 from the San Francisco Groundwater Supply Project, which is a retail project in San Francisco.
Funding approved.
Status on the SF
Groundwater Supply
Project is included in
the callout on Local
Projects in Section 1.
7. Following the development of a water supply strategy, AWS staff will recommend whether to approve participation in the LVE Project before scheduled financial closing in 2024. Based on feasibility analysis to date and in anticipation of a positive staff recommendation, support the SFPUC’s share of funding for the full implementation of the LVE Project. Participation in the LVE Project will also require continued planning for two companion projects:
Conveyance Alternatives for LVE and Supply Alternatives for LVE.
The Los Vaqueros
Expansion Project
was canceled. See
Section 3 for more
details.
8. Continue developing terms of agreement with project partners and prospective recycled water customers. Assuming that terms of agreement will be reached, support funding for completion for final design and construction of the Daly City Recycled Water Expansion Project in the FY 2025-2034 CIP.
The Daly City
Recycled Water
Expansion Project
has been deferred.
See Section 3 for
more details.
Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
16 Recommendation Current Status
9. Include the South Bay Purified Water Project as a new project with funding support through 10% design and environmental review in the FY 2025-2034 CIP. This project supports the evaluation needed to help the SFPUC Commission make a decision regarding the permanent status for the Cities of San Jose and Santa Clara.
Funding approved
and project included
in Capital Plan;
project planning is
underway. See
Section 3.
10. Support funding in the FY 2025-2034 CIP to continue planning through environmental review and 10% design for the PureWater Peninsula and ACWD-USD Purified Water. Support the use of existing funds to continue planning through the Alternatives Analysis for the Calaveras Reservoir Expansion Project.
Funding approved for
PureWater
Peninsula. ACWD-
USD Purified Water
has been deferred.
See Section 3 for
more details.
11. Prioritize planning for operational integration by working with SFPUC operations staff. Support hiring an Operations Planning Manager to begin preparing for system integration, staffing, maintenance, and planning to support development of the AWS Program in the future.
There is currently no
proposed budget
related to this
recommendation.
See Section 2.3.4.
12. Support hiring a Purified Water Program Manager who will be responsible for tracking and ensuring compliance with new regulations, coordination with stakeholders, and establishing a technical advisory panel to support the successful demonstration and implementation of purified water projects within the AWS Program.
Funding approved.
See Section 2.3.4.
13. Prioritize continued coordination with Finance to help track and address long-term project financing options and affordability.
Ongoing. There is no
budget associated
with this
recommendation.
See Section 2.2.
14. Support planning the technical analyses, demonstration, and outreach for PureWaterSF, a local supply project in the retail service area. This work will be supported by the new Purified Water Program Manager and no additional staffing would be needed to support this recommendation at this time.
Funding for initial
planning approved.
Status on the
PureWaterSF Project
is included in the
callout in Section 1.
Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
17 Recommendation Current Status
15. In partnership with BAWSCA, explore the feasibility of a grant program to support local projects that reduce demands on the RWS. No funding or additional resources are needed for this effort at this time.
Scoping for this
recommendation is
underway and
discussions are
planned. See Section
2.3.5. 2.2 Financial Update
In February 2024, the SFPUC adopted the 2-year Operating and Capital Budget and 10-year CIP. Since then, the budget was adopted by the Mayor and Board of Supervisors in July 2024, a final budget was provided to the SFPUC in September 2024 .In January 2025, the Commission conducted a public hearing to review budget priorities for the upcoming FY 2025-26. The FY 2025-26 budget focuses on affordability, responsible management, and sound investment. In February 2025, the SFPUC adopted an amended FY 2025 -26 budge t and update to the 10 -year CIP and 10 -year Financial Plan. This updated budget has been proposed to the Mayor’s Office.
Specific financial updates to AWS projects are as follows:
• Daly City Recycled Water – the project was deferred, making implementation funds previously approved in the capital plan available to other projects • ACWD-USD Purified Water – deferred, making planning funds previously approved in the capital plan available to other projects
• South Bay Purified Water - a new project code was created for this project . Prior to establishing this project code, expenditures for this project were charged to a programmatic fund
• Los Vaqueros Reservoir Expansion – approximately $1.5 million dollars were refunded to the SFPUC following the proje ct’s halt in November 2024. The refund comprised the SFPUC’s share of unused funds from the LVE Joint Powers Authority and was issued as the JPA dissolved. Section 3.2.3 discusses the halt of the project • Calaveras Reservoir Project – the project had been previously deferred, so no significant change in the amended FY 2025-2026 budget
The SFPUC is committed to tracking and addressing long -term project financing options and affordability. In FY 2024-25, staff continued development of a cost model to determine costs for each AWS Project based on a common set of assumptions derived from past SFPUC projects and industry standards. By using consistent assumptions that are based on actual SFPUC capital projects, the SFPUC can have confidence in the AWS Project costs at the current planning level, subject to changes as planning progresses.
Figure 3 shows the dollars spent or encumbered on AWS projects from July 2020 to May 2025.
Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
18 Figure 3. Dollars Spent or Encumbered on Projects to Date (July 2020 – May 2025)
2.3 Programmatic Updates
2.3.1 Negotiations Related to the Agreements to Support Healthy Rivers and Landscapes RECOMMENDATION 3
Continue reporting progress on negotiations related to the Proposed Voluntary Agreement and potential transfers and projects in the San Joaquin Valley that could contribute to instream flow releases. Identify resource and funding needs, as and when appropriate. No new funding or additional resources are needed to support this recommendation.
The Agreements to Support Healthy Rivers and Landscapes is a watershed-wide approach to increase river flows, restore ecosystems, and strengthen water supply reliability across the state. This approach was previously referred to as the “Voluntary Agreements” in the AWS Plan and recommendations. This approach is being developed in an ongoing collaborative decision- making process with the State Water Board and no changes to the current in-stream flow are anticipated until the end of 2025.
2.3.2 Consideration of Permanent Status with San Jose and Santa Clara The Water Supply Agreement states that the Commission will have to make a policy decision by December 31, 2028, on whether to provide a permanent water supply to the Cities of San Jose and Santa Clara. Planning for alternative water supplies is proceeding with the assumption that the Commission may modify the interruptible status of the Cities of San Jose and Santa Clara and provide long-term water supply of 9 mgd to the two cities collectively based on historic deliveries that date back to the 1970s. In addition, San Jose and Santa Clara have requested that the SFPUC consider its anticipated normal year demands for RWS supply of up to 15.5 mgd; this represents 6.5 mgd in excess of the requested combined supply guarantees in years when sufficient RWS supplies are more likely
Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
19 to be available. Given the magnitude of the projected water supply gap, the SFPUC is not planning for any supply guarantee scenario above 9 mgd at this time.
Consistent with the SFPUC’s planning priorities, when evaluating potential AWS supplies, the SFPUC’s existing commitments to meet instream flow requirements and meet ongoing obligations to existing permanent customers must be considered when deciding to ma ke interruptible customers permanent or meeting increased demands of existing and interruptible customers. Distinct from San Jose and Santa Clara’s all -year needs, meeting existing obligations requires securing dry -year supplies, which is the primary objective of the AWS Program.
Since August 2020, BAWSCA has facilitated monthly discussions with San Jose and Santa Clara to collectively consider project opportunities and interests. In addition to reviewing projects that are already listed in the AWS Program, the agencies worked together on other project opportunities that may provide multiple water supply benefits.
In July of 2022 the SFPUC, San Jose, and Santa Clara initiated a feasibility study to evaluate a purified water project concept that can potentially meet both the all -year needs of San Jose and Santa Clara and produce dry-year supplies for the benefit of all RWS customers. Costs for the planning study were shared among the three parties, representing the potential benefits that each may accrue from the project for its customers. Progress on the analysis is described as part of the South Bay Purified Water Project in Section 2.4 of this report.
2.3.3 Projecting Future Demand Scenarios
RECOMMENDATION 5
Based on its assessment in 2024, the SFPUC will develop 1-2 additional demand scenarios for the retail service area including a sensitivity analysis as appropriate to understand the key inputs driving changes in demand. Past projections should be compared to actual deliveries to calibrate the new demand scenario(s). Staff should also collaborate closely with BAWSCA in this effort to track retail and wholesale assumptions.
The SFPUC has started to update its demand forecasting model which would include the development of 1-2 additional retail demand scenarios as described in the AWS Plan Recommendations. This work will inform the calculation of the w ater supply gap and also the SFPUC’s 2025 Urban Water Management Plan. This planning document is required by the California Water Code and supports water suppliers’ long -term resource planning to ensure that adequate water supplies are available to meet existing and future water n eeds. For this effort, the SFPUC will use an econometric model to estimate future water demands using the latest available housing data, employment projection data, and water consumption data. Implementation of this recommendation is ongoing and additional demand scenarios are expected to be finalized by early 2026.
Concurrent with this effort, BAWSCA has started to update their demand model which provides future water demands for its member agencies. Demands from BAWSCA’s study will also be included in future revisions to the water supply gap calculation.
Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
20 2.3.4 Staffing Support
RECOMMENDATION 11
Prioritize planning for operational integration by working with SFPUC operations staff. Support hiring an Operations Planning Manager to begin preparing for system integration, staffing, maintenance, and planning to support development of the AWS Program in the future.
A position was proposed in the budget process, but it was ultimately not approved. It will likely be proposed again as planning progresses. In the meantime, AWS staff meet regularly with the Water Supply and Treatment Division and the Water Quality Division on a programmatic and project-level to identify future operational needs.
RECOMMENDATION 12
Support hiring a Purified Water Program Manager who will be responsible for tracking and ensuring compliance with new regulations, coordination with stakeholders, and establishing a technical advisory panel to support the successful demonstration and imple mentation of purified water projects within the AWS Program.
Three of the six AWS Projects included in the AWS Plan were purified water projects, in addition to the SFPUC developing a local purified water program (i.e., PureWaterSF). Purified water projects require a specialized set of technical, regulatory, and communication skills for successful implementation.
As the scope of these projects was expanding, an AWS Plan recommendation was to support hiring a Purified Water Program Manager who could track new regulations, communicate with stakeholders, provide expertise in the design and quality control of future project demonstration sites.
2.3.5 Supporting Demand Reduction on the Regional Water System RECOMMENDATION 15
In partnership with BAWSCA, explore the feasibility of a grant program to support local projects that reduce demands on the RWS. No funding or additional resources are needed for this effort at this time.
Section 3.06.D of the Water Supply Agreement between the City and County of San Francisco and Wholesale Customers in Alameda County, San Mateo County and Santa Clara County states that “San Francisco and each Wholesale Customer agree that they will diligently apply their best efforts to use both surface water and groundwater sources located within their respective service areas and available recycled water to the maximum feas ible extent, taking into account the environmental impacts, the public health effects and the effects on supply reliability of such use, as well as the cost of developing such sources.”
This AWS Plan Recommendation supports this provision and SFPUC staff are in the initial stage of researching and outlining components of this regional incentive program and have been in Section 2 – AWS Program Highlights and Updates
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
21 discussions with BAWSCA on this joint effort. Research efforts for this program have some overlap with BAWSCA’s Strategy 2050 which is anticipated to be completed by early 2027.
In addition to reducing demands regionally, the SFPUC is also committed to increasing water supply reliability within its retail service area. The SFPUC launched several local supply projects and initiatives, such as PureWaterSF, the Innovations Program, and stormwater capture & reuse projects.
Refer to Section 1.5 for more information about these projects.
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025 Section 3 – Update on AWS Projects
22 Section 3: Update on AWS Projects
The AWS Plan had identified six regional AWS projects that can address the future water supply gap and the priorities for this planning effort. Since the release of this plan in 2024, three projects have been deferred (Daly City Recycled Water Expansion, ACWD -USD Purified Water, and Calaveras Reservoir Expansion) and one project has been canceled (Los Vaqueros Reservoir Expansion). A map of the regional AWS projects is shown in Figure 4.
Beyond these AWS projects, there are additional regional and local efforts that can impact either the projected water supply availability or the demands on the RWS. While these efforts are not specifically part of the AWS Program, there are opportunities f or collaboration in the San Joaquin Valley and local initiatives in San Francisco which are described in Sections 1.5 and 1.6.
3.1 Active Projects
The AWS Program is continuing to pursue the following projects:
• PureWater Peninsula
• South Bay Purified Water
Alameda Creek Watershed Center in Sunol, 2025
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025 Section 3 – Update on AWS Projects
23 Figure 4. Map of AWS Project Locations
LEGEND
1 2
3 4
Existing RWS Pipeline
Other Local Agency Pipeline
South Bay Aqueduct
Potential/Proposed Pipeline
Potential/Proposed Project Facility
Water Treatment
Potential New Outfall
Wastewater Treatment
PureWater Peninsula Project
South Bay Purified Water Project
Regional Conveyance Alternatives
Regional Supply Alternatives
Note: All locations and sizes shown are approximate and represent the general vicinity for potential facilities. Light - shaded circles indicate project facilities associated with each project; they do not indicate project size or volume of water produced.
South Bay
Purified Water
Project
1 2
3 Regional Supply
Alternatives
4 PureWater
Peninsula
Project
Regional
Conveyance
Alternatives
San Andreas
Reservoir
Pilarcitos
Reservoir
Crystal
Springs
Reservoir
Calaveras
Reservoir
San Antonio
Reservoir
Lake Del
Valle
Los Vaqueros
Reservoir
Bethany
Reservoir
Quarry
Lakes
San Francisco
Bay
San Pablo
Reservoir
Briones
Reservoir
San Francisco
Hayward
Sunol
San Leandro
Oakland
Richmond
Danville
Orinda
San Ramon
NOT TO
SCALE
PureWater Peninsula
24 SFPUC Project Manager: YinLan Zhang
PROJECT DESCRIPTION
PureWater Peninsula could provide 6-12 mgd of water supply through either a combination of reservoir water augmentation at Crystal Springs Reservoir, which is a facility of the RWS, and direct potable water reuse through raw water augmentation or treated water augmentation to partner agencies Treated wastewater from Silicon Valley Clean Water and/or the City of San Mateo would be conveyed to an advanced water treatment plant to produce purified water that meets state and federal drinking water quality standards. The purified water would then be delivered to Crystal Springs Reservoir and directly to water purveyors on the Peninsula. Purified water that goes to Crystal Springs Reservoir would be blended with regional surface water supplies and treated again at Harry Tracy Water Treatment Plant. In addition to the SFPUC and the wastewater agencies, Cal Water, Redwood City, Mid- Peninsula Water District and BAWSCA are also participating in the project. Initial feasibility analyses have been completed. Additional planning and preliminary design, including analysis of feasible operational scenarios, impacts to RWS operations and water quality as well as treatment train options, are needed to further develop the project and evaluate its impacts.
GENERAL PROJECT INFORMATION
Avg. Annual Supply Availability Supply Type Local or Regional? Capital Cost/Acre-Foot 6 mgd All Years Purified Water Regional $1,868
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY SFPUC Silicon Valley Clean Water &
City of San Mateo
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative measure that
considers project service area, facilities ownership,
number of project partners, cost share, and whether
SFPUC is the construction and design lead.
Increase dry-year supply reliability Reduce Bay discharges Cal Water BAWSCA / Redwood City /
Mid-Peninsula Water District
Develop local supplies Increase dry-year supply
TOTAL PROJECT COST (2023 DOLLARS) SFPUC BUDGET INFORMATION Estimated Capital Cost Estimated Annual O&M 10-Yr CIP Budget Allocation Current Allocation $1,168M TBD $5.3M $6.8M
ESTIMATED PROJECT SCHEDULE (NOT A BASELINE SCHEDULE)
BENEFITS RISKS AND UNCERTAINTIES
• Reduces Bay discharges.
• Provides a new drought-resistant water supply
• Operational and water quality challenges
• Water supply during non-drought years would impact operations and storage availability in the Regional Water System
• Institutional complexities due to number of partners
Planning
Eng. Design
Env. Review
Permitting
Construction
Public Outreach
2015 2020 2025 2030 2035
Where We Are
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
25 PureWater Peninsula
Current Status – Planning
Current Planning Considerations
To evaluate the merits of the project to produce dry -year water supply, the SFPUC has focused on answering the following planning questions this past year:
1. Which purified water concept, IPR to Crystal Springs or DPR to the RWS should be analyzed in the Alternatives Analysis Report
2. How to introduce the public to the concept of purified water as a new water supply source Activities Conducted this Past Year
By the first half of 2024, the project team had completed the evaluation of two purified water delivery concepts:
1. Indirect Potable Reuse (IPR) / Direct Potable Reuse (DPR) project where between 6 to 8 mgd of purified water would be conveyed to Crystal Springs as IPR and 4 -6 mgd would connect to local water agencies on the peninsula as DPR.
2. DPR-only project using the same advanced water treatment plant as the phased hybrid approach, but with different conveyance alignments that would take the purified water directly into the RWS.
While the phased hybrid and DPR-only concepts would both rely on the same advanced treatment plant that would be located at Silicon Valley Clean Water , the conveyance options for each cover very different geographic areas and would also result in different considerations for SFPUC operations staff.
The focus of this past year has been to decide between the IPR/DPR project or DPR -only project for SFPUC’s Alternatives Analysis Report. To facilitate the decision- making process, SFPUC tasked Kennedy and Jenks to look at potential operational and water quality impacts of IPR to Crystal Springs Crystal Springs Reservoir
$494,000
Dollars spent in
2024-25
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
26 and DPR to the RWS . SFPUC staff, including those from AWS, Water Quality, Water Supply and Treatment, and Communications also toured purified water projects in Southern California to learn from utilities currently producing purified water . The SFPUC concluded that as the first potential purified water project for the agency, a streamlined project with a more defined regulatory path should be the near-term focus, and thus, decided to pursue a 6 -mgd IPR project to Crystal Springs Reservoir using effluent from Silicon Valley Clean Water only. A phase 2 local DPR project that serves water utilities on the peninsula with effluent from San Mateo could be planned at a later stage. The SFPUC and SVCW began work on an MOU that outlines each party’s roles and responsibilities and forms of financial commitments.
On the public engagement front, Communication staff from each partner agency worked together to create a fact sheet that educates the public about purified water and provides some general project information.
Expenditures this year covered the consultant costs for and staff time.
Upcoming Activities in 2025-2026
The SFPUC will initiate a task order for the Alternatives Analysis Report on the 6-mgd IPR project. The SFPUC and SVCW will work to finalize the MOU. Work on public engagement will continue in alignment with outreach activities for PureWaterSF.
South Bay Purified Water
27 SFPUC Project Manager: Fan Lau
PROJECT DESCRIPTION
The SFPUC, the City of San Jose, and the City of Santa
Clara are in the early planning stage of developing a joint purified water project that would serve the local
demands of San Jose and Santa Clara during all types of water years, while also supplementing the water supply
provided through the SFPUC’s Regional Water System
in dry years. An initial concept for a 10 -mgd advanced water treatment facility (i.e., purified water facility) using source water from the San Jose- Santa Clara
Regional Wastewater Faci lity. After the completion of
the study last year, Valley Water joined the partnership.
This initial feasibility study was completed in July 2023.
The project is currently being revised to include Valley Water, maximize utility, and ensure the critical needs of all partners are met. Should the project yield a dry year supply to the SFPUC, this supply would be considered a regional benefit and would be realized only if San Jose and Santa Clara are made permanent customers of the SFPUC, a decision which is to be made by the SFPUC by 2028. Project information here is based on the concept that was analyzed in the feasibility study and will likely be updated in the coming year.
GENERAL PROJECT INFORMATION
Avg. Annual Supply
(based on 2023 feasibility
study)
Availability Supply Type Local or Regional? Capital Cost/Acre-Foot
3.5 mgd Drought and All Years Purified Water Regional $1,264
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY SFPUC City of San Jose, City of Santa
Clara, and Valley Water
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative measure that considers project service area, facilities ownership, number of project partners, cost share, and whether SFPUC is the construction and design lead.
Increase dry-year supply
reliability
Develop local supplies, increase
all-year and dry-year supplies
TOTAL PROJECT COST (2023 DOLLARS) SFPUC BUDGET INFORMATION Estimated Capital Cost Estimated Annual O&M 10-Yr CIP Budget Allocation Current Allocation $658M TBD $6.7M $0M
ESTIMATED PROJECT SCHEDULE (NOT A BASELINE SCHEDULE)
BENEFITS RISKS AND UNCERTAINTIES
• Provides a new drought-resistant supply to San Jose
and Santa Clara
• Provides a water supply option to support San Jose’s
and Santa Clara’s request for permanent status
• Provides a dry-year supply to the Regional Water
System
• Operational and water quality challenges in RWS
transmission system
• Public acceptance of non-traditional water supply
• NPDES compliance related to discharge of reverse
osmosis concentrate (i.e., brine) to San Francisco Bay
• Impacts of enhanced source water control
Planning
Eng. Design
Env. Review
Permitting
Construction
Public Outreach
2020 2025 2030 2035
Where We Are
This figure is based on a 2023 feasibility study.
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
28 South Bay Purified Water
Current Status – Planning
Current Planning Considerations
To evaluate the merits of the project to produce dry -year water supply, the SFPUC considered the following near-term planning questions:
1. Is there a technically viable project that can provide purified water for the Regional Water System customers as well as for local customers of San Jose and Santa Clara?
2. How can benefits be characterized proportionately?
Activities Conducted this Past Year
In 2023, the project partners—SFPUC, City of San Jose, and City of Santa Clara—completed a feasibility study exploring an initial concept of a 10 -mgd advanced water treatment facility that would use source water from the San Jose - Santa Clara Regional Wastewater Facility and operate at
6.5-mgd capacity during wet and normal years. During dry years, the facility would ramp up to the full 10-mgd capacity. The additional 3.5 mgd of purified water produced during dry years would be fed into the RWS to increase dry-year reliability for all SFPUC customers. The feasibility study also explored a larger project intended to maximize available production capacity and considered various options for blending and distribution. The source water flow and quality were characterized based on actual dry-year data to provide a conservative approach and to ensure that the project would be able to operate during dry years.
This past year, Valley Water emerged as a potential partner. Given their experience in implementing purified water, building both public acceptance in its service area and the Silicon Valley Advanced Water Purification Center, Valley Water ’s involvement could increase the project’s potential. In September 2024, the SFPUC, City of San Jose, City of Santa Clara, and Valley Water participated in San Jose-Santa Clara Regional Wastewater Facility
<$1,000
Dollars spent in 2024-
25 within project code
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
29 an in-person workshop to discuss project needs and structure, key roles and responsibilities, and areas for long-term collaboration. Shortly after this workshop, the Cities of San Jose and Santa Clara embarked on developing a project charter with Valley Water . While SFPUC is not involved in this chartering process, the Cities of San Jose and Santa Clara continue to ensure that SFPUC’s interests in a dry-year supply are represented and that SFPUC is apprised of the charter progress.
Starting FY 2024 -25, this project is identified in the CIP with its own dedicated project number.
However, while the project is being restructured to potentially include Valley Water, SFPUC’s capital planning for this project is on hold.
Upcoming Activities in 2025-2026
The project partners will continue to discuss how the project concept can be updated to more fully meet the critical needs of each partner. No timeline has been identified, but SFPUC’s primary driver continues to be its Commission’s 2028 deadline to decide whether or not San Jose and Santa Clara will be made permanent customers. Once a project concept is solidified, the project partners will likely proceed with developing a project description for environmental review and pursue operational feasibility studies. Looking ahead, the key current planning questions for the project are:
1. How can the project be structured to optimize benefits of each partner and possibly accommodate another partner?
2. Where should the new water supply tie into the RWS? How will this affect water quality, operational needs, and distribution of RWS supplies?
3. How does the timeline for the project align with San Jose and Santa Clara’s demand projections?
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
30 3.2 Potential Projects (including Deferred Projects) The AWS Program is investigating the following projects:
• Regional Conveyance Alternatives
• Regional Supply Alternatives
The following projects are currently deferred:
• Daly City Recycled Water Expansion
• SFPUC – Alameda County Water District – Union Sanitary District Purified Water Partnership • Calaveras Reservoir Expansion
Alameda Creek Watershed Center in Sunol, 2025
Regional Conveyance Alternatives
31 SFPUC Project Manager: Lillian Holmes
PROJECT DESCRIPTION
This project was initiated to identify a
pathway to receive water deliveries from
the Los Vaqueros Reservoir Expansion (LVE)
Project in Contra Costa County. Although
the LVE Project has halted (see Section
3.2.3), SFPUC staff are continuing to
evaluate regional conveyance
opportunities. Creation of new conveyance
options could facilitate participation in
water transfers or exchanges for the benefit
of SFPUC's Regional Water System (RWS)
customers. SFPUC staff will continue to
investigate potential use of the South Bay
Aqueduct (SBA) in partnership with the California Department of Water Resources (DWR). In addition to DWR, potential partners include the SBA Contractors (ACWD, Zone 7 Water Agency, and Valley Water) and any agency identified as a feasible transfer partner. Conveyance via the SBA would likely require pipeline improvements and may also include pretreatment and/or pumping. In addition to conveyance via the SBA, SFPUC continues to consider other transfer or exchange opportunities, including the potential for a new intertie with the East Bay Municipal Utility District (EBMUD).
GENERAL PROJECT INFORMATION
Avg. Annual Supply Availability Supply Type Local or Regional? Capital Cost/Acre-Foot See Regional Supply
Opportunities All Years Transfer Regional $1,700-$4,027
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY DWR ACWD and Valley Water or
EBMUD
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative measure that considers project service area, facilities ownership, number of project partners, cost share, and whether SFPUC is the construction and design lead.
Provides conveyance and
approvals
Provide water exchange and
treatment opportunities
TOTAL PROJECT COST (2023 DOLLARS) SFPUC BUDGET INFORMATION Estimated Capital Cost Estimated Annual O&M 10-Yr CIP Budget Allocation Current Allocation $7M-$9M $0.1M-$5M $4.3M $2.0M
ESTIMATED PROJECT SCHEDULE (NOT A BASELINE SCHEDULE)
BENEFITS RISKS AND UNCERTAINTIES
• Leverages existing infrastructure
• For exchanges (with ACWD and VW) treatment
will be delegated to a partner familiar with SBA
as a source
• Evaluation of existing infrastructure requires full SBA shut down, which impacts existing users
• Institutional arrangements/willingness of stakeholders • Treatment and pre-treatment in some cases
• Water quality challenges associated with a new source of supply Planning
Eng. Design
Env. Review
Permitting
Construction
Public Outreach
2019 2024 2029
Where We Are
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
32 Regional Conveyance Alternatives
Current Status – Planning
Current Planning Considerations
Identifying a viable conveyance pathway is critical for the SFPUC’s access to water transfers or exchanges, as well as participation in potential regional projects. The primary focus of this task has been to understand the capacity within the South Bay Aqueduct (SBA) and evaluate an alternative through the East Bay Municipal Utility District service area.
Activities Conducted this Past Year
Staff submitted an updated official request to DWR for modification for use of an existing South Bay Aqueduct turnout near San Antonio Reservoir located at SBA’s milepost 21.82. The San Antonio Turnout was built in the late 1980s and has not been operated for over 30 years. In 2024, DWR conducted a Phase 1 Inspection of the 30” turnout and supporting structures, finding that while two of the three vaults appear to be in good condition, the energy dissipater vault shows signs of coating delamination and severe corrosion on bolts and flanges. Subsequent testing of the turnout would require an outage of the SBA, which must be scheduled in close coordination with DWR and SBA users. The SFPUC will work with DWR and the SBA contractors to identify windows of opportunity that may exist for such evaluation.
Upcoming Activities in 2025-2026
Activities expected to take place in the next year are as follows:
Staff will continue to engage with DWR to develop an estimate of infrastructure needs and costs for use the existing San Antonio Turnout
Staff will work with DWR to understand the process for turnout modification requests and explore ways of funding modifications
South Bay Aqueduct
$13,000
Dollars spent
in 2024-25
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
33 Staff will continue to explore transfer and exchange opportunities with potential partners Staff will continue to assess the viability of this conveyance pathway in light of the expected costs associated with turnout modifications, the potential for invasive species issues, and the required interagency partnerships.
Regional Supply Alternatives
34 SFPUC Project Manager: Lillian Holmes
PROJECT DESCRIPTION
This project was initiated to identify a water
supply to be stored in the expanded Los
Vaqueros Reservoir. Although the reservoir
expansion project has halted, the SFPUC
continues to investigate regional supply
opportunities, primarily transfers and new
water supplies generated by advanced
treatment of wastewater, brackish water,
or groundwater. Such supply alternatives
could provide 4 to 5 mgd of storage in
normal and dry years. One supply
alternative is the proposed Bay Area
Brackish Water Desalination (Regional
Desalination) Project, which is a
partnership between CCWD, SFPUC, the
Santa Clara Valley Water District, Zone 7 Water Agency, and potentially EBMUD. The project could provide a new drinking water supply to the region by treating brackish water from CCWD's existing Mallard Slough intake in Contra Costa County.
Another supply alternative is the purchase of water transfers from willing sellers in the San Francisco Bay Delta (Delta).
GENERAL PROJECT INFORMATION
Avg. Annual Supply Availability Supply Type Local or Regional? Capital Cost/Acre-Foot To be identified
Dry Years (with
storage) and/or
All Years
Desalination /
Transfers Regional $1,700-$4,027
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY Water Sellers in the Delta Contra Costa Water District
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative measure that considers project service area, facilities ownership, number of project partners, cost share, and whether SFPUC is the construction and design lead.
Generates revenue Facilitate potential
partnership
TOTAL PROJECT COST (2023 DOLLARS) SFPUC BUDGET INFORMATION Estimated Capital Cost Estimated Annual O&M 10-Yr CIP Budget Allocation Current Allocation $3M-$10M $3M-$10M $6.7M $3.5M
ESTIMATED PROJECT SCHEDULE (NOT A BASELINE SCHEDULE)
BENEFITS RISKS AND UNCERTAINTIES
• Availability during dry years
• Lower GHG emissions than seawater desalination
• Leverages existing infrastructure
• Some impacts to sensitive fish may be unavoidable
• Water rights and permitting likely to be challenging
• Conveyance options are limited to transfer water to RWS • Exchange ratio is unclear/under evaluation with Central Valley Project
Planning
Eng. Design
Env. Review
Permitting
Construction
Outreach
2015 2020 2025 2030 2035 2040
Where We ArePlanning (resumed)
Public Outreach (resumed)
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
35 Regional Supply Alternatives
Current Status – Planning
Current Planning Considerations
This project began as a way to identify potential water supply sources for storage in the now-canceled LVE project. However, the supply alternatives under study —transfers and/or a regional desalination or water purification project—continue to offer potential dry-year supplies for the benefit of the RWS.
As the SFPUC further explores these options, planning considerations include:
• Cost and institutional complexity of a regional desalination or other advanced water treatment project
• Losses associated with transfers/exchanges and related conveyance • Water treatment and invasive species management required to take Delta supplies Activities Conducted this Past Year
The SFPUC evaluated water supply alternatives in relation to the Los Vaqueros Reservoir Expansion that was then still active .
Following the halt of the reservoir expansion project, staff continued to explore possible supply options, including water transfers from willing sellers. Staff further developed institutional relationships related to potential water transfers.
Upcoming Activities in 2025-2026
Staff will continue to explore the feasibility of water transfers with potential sellers in the Delta. Staff will remain in conversation with regional partners regarding potential future desalination and water purification efforts.
Mallard Slough Pump Station
$26,000
Dollars spent in
2024-25
Daly City Recycled Water Expansion (deferred)
36 SFPUC Project Manager: YinLan Zhang
PROJECT DESCRIPTION
This was a recycled water project intended to produce
approximately 1.0 mgd of recycled water on an average
annual basis, resulting in approximately 0.7 mgd of
additional dry -year potable supply availability in the South Westside Groundwater Basin. The primary purpose of this project was to provide recycled water to certain cemeteries and other smaller irrigation customers, offsetting existing groundwater pumping from, and therefore enhancing the
reliability of, the South Westside Groundwater Basin.
SFPUC customers were intended to benefit from a portion of the increased reliability of the South Westside
Groundwater Basin for additional drinking water supply
during droughts.
GENERAL PROJECT INFORMATION
Avg. Annual Supply Availability Supply Type Local or Regional? Capital Cost/Acre-Foot
0.7 mgd Drought Years
and/or All Years
Recycled Water /
Groundwater Offset Regional $4,203
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY SFPUC Daly City (Sanitation
District) Cal Water
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative measure that considers project service area, facilities ownership, number of project partners, cost share, and whether SFPUC is the construction and design lead.
Increase dry-year
water supply reliability
Reduce ocean
discharges
Develop local
supplies
TOTAL PROJECT COST (2023 DOLLARS)
Estimated Capital Cost Estimated Annual O&M
$120M TBD
BENEFITS RISKS AND UNCERTAINTIES
• Enhance basin sustainability and groundwater supply
• Avoid mitigation requirements for Groundwater Storage and Recovery Project (GSR)
• Offset approximately 0.05 mgd of potable water
currently sed for irrigation
• Securing customers (cemeteries and others)
• Partner buy-in and involvement
• Finalizing and securing storage tank location
• Realizing groundwater offset benefits through GSR
• Potential loss of 1-2 SFPUC retail customers
ACTIVITIES CONDUCTED THIS PAST YEAR REASON FOR DEFERAL
• At the beginning of 2025, SFPUC staff re -evaluated the financial feasibility of the project. In the most recent update of capital costs for the AWS Plan, the total cost of the project had risen to $120 million, with a significant share of that cost to be b orne by the SFPUC. With a corresponding groundwater benefit of approximately 0.4 - 0.7 mgd for the SFPUC, staff considered whether there was a more cost -effective alternative available and evaluated an alternative project using effluent from San Francisco International Airport.
Results show that an alternate project would not be less costly. Therefore, SFPUC has deferred this project from the 10 -year capital plan. The project may resume if and when conditions change.
• Due to limited and reducing water
supply benefits to the SFPUC, this
project has been deferred. This
project may be reevaluated should
water shortage projections persist
in the future.
SFPUC - Alameda County Water District – Unition Sanitary District Purified Water Partnership (deferred)
37 SFPUC Project Manager: YinLan Zhang
PROJECT DESCRIPTION
This project was intended to provide a new purified water supply utilizing Union Sanitary District (USD)'s treated wastewater and further treating it through a multi -barrier advanced treatment process to meet or exceed drinking water standards. Purified water produced at USD could be transmi tted to the Quarry Lakes Groundwater Recharge Area to supplement recharge into the Niles Cone Groundwater Basin or for other uses in Alameda County Water District's (ACWD's) service area. With the additional water supply of up to 5.4 mgd in a first phase to ACWD, an in- lieu exchange with the SFPUC was intended to result in more water left in the SFPUC's Regional Water System.
GENERAL PROJECT INFORMATION
Avg. Annual Supply Availability Supply Type Local or Regional? Capital Cost/Acre-Foot
5.4 mgd All Years Purified Water Regional $4,541
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY SFPUC Alameda County
Water District
Union Sanitary
District
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative measure that considers project service area, facilities ownership, number of project partners, cost share, and whether SFPUC is the construction and design lead.
Increase dry-year
water supply reliability
Reduce dependence
on SFPUC Regional
Water System
Reduce Bay
discharges
TOTAL PROJECT COST (2023 DOLLARS)
Estimated Capital Cost Estimated Annual O&M
$1,301M TBD
BENEFITS RISKS AND UNCERTAINTIES
• Leverages existing facilities to provide water supply • Uncertainty of planned capital improvements at wastewater treatment plant may affect purified water
treatment requirements
• Potential water quality change to Quarry Lakes
• Finding suitable suite for advanced water purification facility
ACTIVITIES CONDUCTED THIS PAST YEAR REASON FOR DEFERAL
• No new activities conducted this past year. • Both USD and ACWD are currently pursuing other priority planning efforts. This project may be
reevaluated should the partner agencies require
additional supply from this project in the future.
Calaveras Reservoir Expansion (deferred)
38 SFPUC Project Manager: Susan Hou
PROJECT DESCRIPTION
Calaveras Reservoir, located in Alameda and Santa Clara counties, currently stores water from the local Alameda Creek Watershed. This project evaluated the possibility of making the reservoir larger to also store water from our Regional Water System. No expansion of water rights from the local watershed was anticipated. An expanded
reservoir could hold an additional 94 billion gallons of water storage, up from the current 31 billion gallons.
The proposed project would include raising the New
Calaveras Dam, increasing the capacity of the outlet
structures and the spillway, and the addition of any
transmission and pumping facilities needed to bring water from the Regional Water System to Calaveras Reservoir. Constraints including water availability and transmission to the reservoir would need to be further evaluated.
GENERAL PROJECT INFORMATION
Avg. Annual Supply Availability Supply Type Local or Regional? Capital Cost/Acre-Foot
2.7-28.6 mgd Drought Years
and/or All Years Local Storage Regional $2,831-$3,960
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY SFPUC
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative measure that considers project service area, facilities ownership, number of project partners, cost share, and whether SFPUC is the construction and design lead.
Increase dry-year supply reliability
TOTAL PROJECT COST (2023 DOLLARS)
Estimated Capital Cost Estimated Annual O&M
$346M - $6,011M TBD
BENEFITS RISKS AND UNCERTAINTIES
• Provides operational flexibility, particularly in dry years • Increases storage capacity in the SFPUC’s largest
reservoir
• Increases utilization of Tuolumne River and other
wet/normal year supply
• Operational and water quality challenges
• Water supply during non-drought years would impact
operations and storage availability in the RWS
• Institutional complexities due to number of partners
ACTIVITIES CONDUCTED THIS PAST YEAR REASON FOR DEFERAL
• No significant work was done on this project because it was deferred early in this reporting period.
• Due to significant upfront capital costs and complex
engineering conveyance requirements, this project has
been deferred. This project may be reevaluated after
2026 when the AWS Plan is expected to be updated.
Section 3 – Update on AWS Projects
39 3.3 Canceled Project
The AWS Program is not actively planning for the following project:
• Los Vaqueros Reservoir Expansion
Alameda Creek Watershed Center in Sunol, 2025
Los Vaqueros Reservoir Expansion (canceled)
40 SFPUC Project Manager: Lillian Holmes
PROJECT DESCRIPTION
The Los Vaqueros Reservoir Expansion (LVE) Project was a storage project intended to enlarge the existing reservoir located in Contra Costa County from 160,000 acre-feet to 275,000 acre-feet. The expansion sought to increase water supply reliability for municipal, industrial, and agricultural customers as well as provide ecosystem benefits to south of Delta wildlife refuges and Delta fisheries. The existing reservoir is owned and operated by Contra Costa Water District (CCWD), and a Joint Powers Authority (JPA) formed in October 2021 to pursue the expansion. As owner of the existing reservoir, CCWD halted the project in November 2024 due to concerns over rising costs and decreasing water supply benefits. The JPA was subsequently dissolved. The SFPUC was interested in participating in the project to secure storage to increase dry-year water supplies. Although the JPA has dissolved, the SFPUC continues to collaborate with partner agencies regarding regional drought preparedness.
GENERAL PROJECT INFORMATION
Avg. Annual Supply Availability Supply Type Local or Regional? Capital Cost/Acre-Foot
3.9 mgd Drought Years
and/or All Years Storage Regional $1,700-$4,027
PROJECT PARTNERS AND INTERESTS INSTITUTIONAL COMPLEXITY CCWD & EBMUD ACWD & Zone 7 Water
Agency & Valley Water SFPUC (with BAWSCA)
SFPUC
Only
Multi-Party
Partnership
Institutional complexity is a relative
measure that considers project service
area, facilities ownership, number of
project partners, cost share, and whether
SFPUC is the construction and design lead.
Increase water supply
reliability
Increase water supply
reliability
Increase dry-year supply
reliability
San Luis & Delta Mendota
Water Authority Grassland Water District DWR (State) & USBR (Federal)
Increase water supply for
irrigation Protect wildlife refuges Provide approvals and funding
TOTAL PROJECT COST (2023 DOLLARS)
Estimated Capital Cost Estimated Annual O&M
$286M - $792M $7M - $15M
BENEFITS RISKS AND UNCERTAINTIES
• Provides operational flexibility, particularly in dry years • Allows the SFPUC to manage existing supplies more efficiently • Capacity and institutional constraints for
conveyance to RWS
• Firm source of water supply
• Water quality risks and treatment needs,
depending upon conveyance pathway
ACTIVITIES CONDUCTED THIS PAST YEAR REASON FOR CANCELLATION • Discussion of Contract for Administration of Public Benefits with California Department of Fish and Wildlife regarding reduction in diversions required by changes to Incidental Take Permit. • Analysis and negotiation among JPA members regarding storage allocation, Facility Usage Agreement, Design and Construction Agreement, Backstop Agreement, and LVE JPA Agreement.
• Further development of SFPUC business case for participation in LVE, including exploration of water supply options.
• The project was canceled in fall 2024 by
Contra Costa Water District due to concerns
over project risks, rising project costs, and
decreasing water supply benefits.
Section 3 – Update on AWS Projects
ALTERNATIVE WATER SUPPLY – ANNUAL PROGRESS REPORT – 2024-2025
41 3.3 Looking Ahead
AWS Projects, by their very nature, are more complex than traditional surface water supply projects that are fully under the control of the SFPUC. Therefore, careful analysis of technical, institutional, and financial feasibility is particularly important. As planning for the AWS Program has demonstrated over the past five years, some projects may not be feasible at the time of assessment for one or more reasons. It is still prudent to identify and analyze potential opportunities.
Looking ahead, planning uncertainties remain and diversifying the SFPUC’s supplies to improve dry year reliability remains a priority. Purified water provides a sustainable supply source that can help meet that goal. As utilities across California and the world pursue purified water projects, the SFPUC should collaborate with water and wastewater utilities to help build successful dry year supplies while also encouraging actions to reduce reliance on surface water supplies and improve the efficient use and distribution of our existing supplies.
Sunol Water Temple, 2024