AGENDA ITEM
Public Utilities Commission
City and County of San Francisco
DEPARTMENT: Water Enterprise
AGENDA NUMBER: 9
MEETING DATE: September 8, 2026
Calendar: Regular Calendar
Project Manager: Jennifer Lee
Approve Water Supply Assessment for the Treasure Island Residential Program Modification Project
Summary of Proposed
Commission Action:
Approve the Water Supply Assessment for the proposed Treasure Island Residential Program Modification Project, pursuant to California Water Code Section 10910 et seq., California Environmental Quality Act (CEQA) Section 21151.9, and CEQA Guidelines Section 15155.
Background: California’s Water Supply Assessment law (California Water Code (Water Code) Sections 10910- 10915) provides a nexus between the regional land use planning process and the environmental review process. The law also reflects the need to incorporate water supply and demand analysis at the earliest possible stage in the land use planning process. The core of this law is the requirement for a public water system, such as the San Francisco Public Utilities Commission (SFPUC), to prepare a Wat
er Supply Assessment
(WSA) on whether available water supplies are sufficient to serve the demand generated by projects of a specified size (water demand projects), as well as the reasonably foreseeable cumulative demand in the region over the next 20 year s under a range of hydrologic conditions. The WSA is subject to Commission approval.
The San Francisco Planning Department carries out the City’s lead agency responsibilities under CEQA and is
preparing an
Environmental Impact Report Addendum for the proposed Treasure Island Residential Program Modification Project (the Project). The Project is located on Treasure Island and the project sponsor, Treasure Island Community Development, LLC , proposes to add up to 2,800 residential units to the approved Treasure Island/Yerba Buena Island Redevelopment Project.
In reviewing the Project, the Planning Department determined that it qualifies as a water demand project and therefore requires preparation of a WSA because it is a residential development that would include more than 500 dwelling units.
The content of a WSA is specified by the Water Code and includes identification of any existing water supply entitlements or contracts and information about groundwater supplies. It assesses the Agenda Title: Approve Water Supply Assessment for the Treasure Island Residential Program Modification Project Commission Meeting Date: September 8, 2026
adequacy of water supplies to serve the proposed project and cumulative demand.
The WSA must be completed by the public water supplier that would serve the proposed project and be approved by its governing body at a public meeting. Approval of a WSA is not approval of the development project for which the WSA is prepared. A WSA is an informational document required to be prepared for use in the City’s environmental review of a proposed project under CEQA. As discussed in the WSA prepared for the Project, the
Project has
already been accounted for in SFPUC’s water supply planning as described in the 2025 Urban Water Management Plan.
The proposed WSA analyzes the sufficiency of long- term water supplies to serve the Project and cumulative development over a 20-year projection. In December 2018, the State Water Resources Control Board (SWRCB) adopted amendments to the Water Quality Control Plan for the San Francisco Bay/Sacramento- San Joaquin Delta Estuary (Bay -Delta Plan Amendment). The City, along with multiple other water agencies, filed suit in early 2019 challenging the validity of the Bay -Delta Plan Amendment. That lawsuit, which is consolidated with other legal challenges, is currently pending before the California Court of Appeal, Third District. In January 2021, the SWRCB moved to implement the Bay -Delta Plan
Amendment on the Tuolumne River by issuing a water quality certification under Section 401 of the Clean Water Act in the Federal Energy Regulatory Commission (FERC) licensing proceedings for the hydropower projects associated with the New Don Pedro and La Grange dams. The City and other water users on the Tuolumne River filed legal and administrative challenges to these SWRCB actions. The SWRCB has since set aside the water quality certification and withdrawn it from the FERC record, and FERC has not yet reissued a license for the New Don Pedro Hydropower Project. Alongside the water quality certification, on August 8, 2022, the SWRCB issued a CEQA Notice of Preparation for an alternative means of implementing the Bay-Delta Plan Amendment. Any future amendments to or implementation of the Bay -
Delta Plan
Amendment may be subject to further legal challenges.
Recognizing the obstacles to implementing the Bay -Delta Plan Amendment, the SWRCB, by Resolution No. 2018- 0059 adopted the Bay-Delta Plan Amendment and directed SWRCB staff to help complete a “Delta watershed- wide agreement, including potential flow measures for the Tuolumne River” by March 1, 2019, and to incorporate such agreements as an “alternative” for a future amendment to the Bay-Delta Plan to be presented to the SWRCB “as early as possible after December 1, 2019.” In accordance with the SWRCB’s dire ctive
, on March 1, 2019, the SFPUC, in
partnership with other key interested parties, submitted a proposed Agenda Title: Approve Water Supply Assessment for the Treasure Island Residential Program Modification Project Commission Meeting Date: September 8, 2026
project description for the Tuolumne River that could form the basis for an agreement (Tuolumne River Healthy Rivers and Landscapes Program) to the SWRCB that would serve as an amendment to the Bay-Delta Plan. On March 26, 2019, the SFPUC adopted
Resolution No. 19-0057 to support its participation in the Tuolumne River Healthy Rivers and Landscapes Program negotiation process. In November 2022, the SFPUC and partner water
agencies on the Tuolumne River signed onto a non- binding Memorandum of Understanding b etween the State and other parties to structure their participation in the Tuolumne River Healthy Rivers and Landscapes Program negotiation process. This framework document is designed to facilitate the parties’ development of enforceable agreements and amendments to the Bay-Delta Plan, with actions and funding to integrate additional water flows with the physical landscape to help improve habitat for native fish in the Sacramento- San Joaquin River Delta watershed, including the Tuolumne River. On March 29, 2024, in furtherance of the Memorandum of Understanding, the SFPUC submitted the key components of its proposed Tuolumne River
Healthy Rivers and
Landscapes Program to the SWRCB. On September 19, 2025, SWRCB issued a report describing the scientific basis in support of the Tuolumne River Healthy Rivers and Landscapes Program, which SWRCB will use to inform its consideration of the agreement.
The SFPUC continues to actively participate in this process and as of the date of the issuance of the WSA for the Pr oject , those
negotiations remain ongoing.
Implementation of the Bay -Delta Plan Amendment is uncertain given the ongoing negotiations, litigation, and regulatory proceedings. Given the current uncertainty regarding the extent and timing of implementation of the Bay -Delta Plan Amendment, th e Project’s WSA analyzes water supply and demand through 205 0 under three scenarios:
• Scenario 1: No implementation of the Bay -Delta Plan
Amendment;
• Scenario 2: Implementation of the Tuolumne River Healthy Rivers and Landscapes Program; and,
• Scenario 3: Implementation of the Bay -Delta Plan
Amendment.
The WSA concludes that:
• During normal years, the SFPUC’s total projected water supplies will meet the projected demands of its retail
customers, including those of the Project, existing
customers, and foreseeable future development under
Scenario 1, Scenario 2, and Scenario 3.
• During single dry years and multiple dry years under
Scenario 1 (No implementation of the Bay -Delta Plan
Amendment), the SFPUC can meet the projected demands
Agenda Title: Approve Water Supply Assessment for the Treasure Island Residential Program Modification Project Commission Meeting Date: September 8, 2026
of its retail customers, including those of the Project, existing customers, and foreseeable future development while
remaining within its Level of Service goal of limiting system- wide water use reductions to 20%.
• During single dry years and multiple dry years under
Scenario 2 (Implementation of the Tuolumne River Healthy Rivers and Landscapes Program) , the SFPUC c ould still face a shortfall, thus requiring water use reduction, but to a lesser degree and in closer alignment to the Level of Service goal of no more than 20% system-wide water use reduction compared to that which would occur under Scenario 3.
• During single dry years and multiple dry years under
Scenario 3 (Implementation of the Bay -Delta Plan
Amendment), the SFPUC cannot reliably meet the projected demands of its retail customers, including the Project, existing customers, and foreseeable future development, without water use reduction at a level greater than that required to achieve the Level of Service goal of a maximum of 20% system -wide average water use reduction. The
SFPUC estimates it would impose up to 29% water use
reductions across the retail service area.
• The SFPUC’s Water Shortage Contingency Plan describes allocation methods and processes that may be used in future droughts. For both residential and commercial customers, the SFPUC may implement varying levels of water use
reductions based on the baseline level of water use, e.g., require less reduction from customers that use less water to begin with. For the Project specifically, these policies may result in lower levels of mandatory water use reduction because of the installation of water -efficient plumbing fixtures.
• Under Scenario 3, the relatively small volume of water demand generated by the Project would not exacerbate the projected shortfalls resulting from implementation of the Bay- Delta Plan Amendment. Regardless of whether the Project is constructed, with imple mentation of the Bay -
Delta Plan
Amendment, the SFPUC’s existing and planned water
supplies will not meet the water demands of its retail service area in dry years without significant demand reductions.
Environmental
Review:
This action does not constitute a project under the California Environmental Quality Act (CEQA) Guidelines Section 15378 because it will not result in a physical change in the environment , and it does not represent an approval of a specific project. Pursuant to California Water Code Sections 10910- 10915 and CEQA Guidelines Section 15155, a Water Supply Assessment is an informational requirement undertaken during environmental review.
Its purpose is to evaluate the sufficiency of available water supplies to meet the demands of the proposed project.
Agenda Title: Approve Water Supply Assessment for the Treasure Island Residential Program Modification Project Commission Meeting Date: September 8, 2026
Attachment: 1. Water Supply Assessment for the Treasure Island Residential Program Modification Project
PUBLIC UTILITIES COMMISSION
City and County of San Francisco
RESOLUTION NO. __________________
WHEREAS, Under the California Environmental Quality Act (CEQA) and California Water Code Section 10910(g)(1), the San Francisco Public Utilities Commission (SFPUC) is required to prepare and approve a Water Supply Assessment of whether available water supplies are sufficient to serve the demand generated by projects of a specified size and the reasonably foreseeable cumulative demand in the region over the next 20 years under a range of hydrologic conditions; and
WHEREAS, The Treasure Island Residential Program Modification Project (Project) is located on Treasure Island; and
WHEREAS, The project sponsor, Treasure Island Community Development, LLC, proposes to add up to 2,800 residential units to the development without any significant changes to the zoning envelope or horizontal development footprint; and
WHEREAS, The Project requires the preparation of a Water Supply Assessment because it is a residential development that includes more than 500 dwelling units; and
WHEREAS, A Water Supply Assessment must be completed by the public water supplier that would serve the proposed project and be approved by its governing body at a public meeting; and
WHEREAS, This action does not constitute a project under the California Environmental Quality Act (CEQA) Guidelines Section 15378 because it will not result in a physical change in the environment, and it does not represent an approval of a specific project; and
WHEREAS, Pursuant to California Water Code Sections 10910-10915 and CEQA Guidelines Section 15155, a Water Supply Assessment is an informational requirement undertaken during environmental review, and its purpose is to evaluate the sufficiency of available water supplies to meet the demands of the proposed project; and
WHEREAS, The water demand associated with the Project is encompassed within the 2025 Urban Water Management Plan water demand projections; and
WHEREAS, SFPUC staff prepared the attached Water Supply Assessment for the Project, analyzing water supply and demand under three scenarios: (1) No implementation of the Bay-Delta Plan Amendment (Scenario 1), (2) Implementation of the Tuolumne River Healthy Rivers and Landscapes Program (Scenario 2), and (3) Implementation of the Bay-Delta Plan Amendment (Scenario 3); and
WHEREAS, The Water Supply Assessment concludes that the SFPUC’s total
projected water supplies through 2050 will (1) meet the demands of the Project in normal years under all three scenarios, (2) meet the demands of the Project in dry years without rationing beyond the SFPUC’s level of service (LOS) goal of no more than 20% system - wide rationing under Scenario 1, (3) require water use reduction but to a lesser degree and in closer alignment to the LOS goal of no more than 20% system -wide water use reduction under Scenario 2 and in comparison to Scenario 3; and (4) not reliabl y meet the projected demands of the Project without rationing at a level greater than that required to achieve the LOS goal under Scenario 3; and
WHEREAS, In dry years, the Project may have lower levels of mandatory water use reduction compared to existing buildings because of the installation of water-efficient plumbing fixtures; and
WHEREAS, The relatively small volume of water demand generated by the Project itself would not exacerbate the projected shortfalls resulting from implementation of the Bay-Delta Plan Amendment; now, therefore, be it
RESOLVED, This Commission hereby approves the attached Water Supply Assessment for the Treasure Island Residential Program Modification Project pursuant to the California Water Code Section 10910(g).
I hereby certify that the foregoing resolution was adopted by the San Francisco Public Utilities Commission at its meeting of September 8, 2026.
__________________________________
Director of Commission Affairs
San Francisco Public Utilities Commission