Other Regional Partnerships

Eight of the Bay Area’s largest water utilities formed a partnership in 2016 to explore opportunities to transfer and exchange water between water utilities to meet water supply demands, particularly during droughts and emergencies. The intent is to leverage existing infrastructure and connections that already exist between the partnering agencies.

Called the Bay Area Regional Reliability (BARR) Partnership, the group includes the following member agencies: 1) Alameda County Water District (ACWD), 2) Bay Area Water Supply & Conservation Agency (BAWSCA), 3) Contra Costa Water District (CCWD), 4) East Bay Municipal Utility District (EBMUD), 5) Marin Municipal Water District (MMWD), 6) the San Francisco Public Utilities Commission (SFPUC), 7) Valley Water (formerly Santa Clara Valley Water District and 8) Zone 7 Water Agency.

The SFPUC is assessing possible conveyance pathways between the Regional Water System and partner agencies to expand the SFPUC’s access to water transfer markets and potential future multi-agency alternative water supply facilities. The conveyance assessment effort was initiated to facilitate the SFPUC’s participation in the Los Vaqueros Reservoir Expansion and has continued beyond the halt of the expansion effort.

Several alternatives under consideration involve use of the South Bay Aqueduct, including delivery to San Antonio Reservoir and exchanges with regional partners. Potential partners include the South Bay Aqueduct Contractors (ACWD, Zone 7 Water Agency, and Valley Water), particularly any agency identified as a feasible transfer partner. Of the current options, only delivery to San Antonio Reservoir would involve direct transfer of South Bay Aqueduct water into the SFPUC’s Regional Water System. All conveyance options currently under consideration depend upon reliable delivery through the South Bay Aqueduct, a State Water Project facility owned and operated by the California Department of Water Resources. 

In addition to these conveyance options, other conveyance opportunities may be viable, such as construction of a new intertie with the East Bay Municipal Utility District (EBMUD).

Together with several fellow Bay Area water agencies, the SFPUC investigated the possibility of treating brackish water (water with more salinity than freshwater but less than sea water) from Contra Costa Water District’s existing Mallard Slough intake in Contra Costa County. This project would rely on available capacity in an extensive network of existing pipelines and facilities that already connect the agencies. It would also require the construction of new facilities and upgrades to existing infrastructure to accomplish.

This project was explored in partnership with: Contra Costa Water District (CCWD), SFPUC, Valley Water, and Zone 7 Water Agency. Other potential partners included East Bay Municipal Utility District (EBMUD) and the Alameda County Water District (ACWD).

The project could provide 10 to 20 million gallons of a new drinking water supply for all of these participating water agencies. The SFPUC would not directly receive desalinated water but would take delivery of water through a series of transfers and exchanges.

Called Inter-Basin Collaborations, this is a partnership among several agencies in a river basin that can take advantage of the annual hydrology of each river system to mutual benefit. For example, one river system in the basin may spill more excess water in wet years than another river system and the excess water could be used to meet either fishery requirements or other needs to allow the other river system to retain water in storage. Then the stored water could be used in dry years to provide the water to meet obligations in both river systems. Inter-Basin collaborations could also take the form of groundwater banking or water transfers.

There are a number of potential collaborations among and between the San Joaquin tributaries that could develop additional water supplies, some of which could be utilized to enhance fishery flows. There are also potential collaborative non flow measures (i.e. improved and augmented hatchery activities on the Merced River) that could benefit all of the tributaries.

A feasibility study of this option is included in the proposed Tuolumne River Voluntary Agreement. Any collaboration would need to protect the interests of all participants.

This project has been deferred. The project evaluated providing recycled water to irrigate cemeteries in Colma and a few smaller irrigation customers in Daly City to replace groundwater use from the South Westside Basin. By irrigating with recycled water, the project would save the groundwater for drinking. The recycled water would come from Daly City’s Wastewater Plant, which could produce up to 3 million gallons of water per day of recycled water during the irrigation season.

The SFPUC worked closely with Daly City, California Water Service Company’s (Cal Water), and the irrigation customers located within Cal Water’s service area. 

Additional information can be found in the following reports:

• Combined Results of the Recycled Water Treatment and Delivery System Expansion Feasibility Studies (Carollo, 2009)
• Final Initial Study/Mitigated Negative Declaration (IS/MND) (SMB Environmental, 2017)
• Preliminary Design Report and 30% Drawings (Volume 1, Volume 2, Volume 3) (Carollo, 2017)
• Feasible Alternatives Evaluation (Carollo, 2022)

In 2024, the San Francisco International Airport began a project to upgrade its existing recycled water system. The upgrade will provide more non-potable, or non-drinking, water. This project may produce more recycled water than the Airport needs. The SFPUC and the Airport conducted a study to see if the surplus could be used outside of the Airport. SFPUC customers who use the recycled water would offset their demands from the Regional Water System. The study is available below. For now, no further planning is underway.

• San Francisco International Airport Water Reuse Evaluation (Carollo, 2025)