Water from Hetch Hetchy Reservoir accounts for up to 85% of the water the San Francisco Public Utilities Commission delivers each year, according to its 2025 Annual Water Quality Report. The rest comes from local reservoirs in Alameda and San Mateo counties and from groundwater. In FY2025 SFPUC sold about 66,444 million gallons, roughly 182 million gallons a day, to a service population of about 2.7 million people.
Storage, not new supply
SFPUC ended FY2025 with 63,579 million gallons in regional reservoirs and 413 million gallons in the city. Its main addition this decade is underground: the Regional Groundwater Storage and Recovery Project can bank up to 20 billion gallons for dry years, with its last phase forecast for December 7, 2027. Mountain Tunnel, which SFPUC calls a non-redundant link in the regional system, is forecast to finish on June 3, 2027.
Projects pushed back
Bigger supply projects have stalled. Contra Costa Water District canceled the Los Vaqueros Reservoir expansion in fall 2024. SFPUC lists the expansion of Calaveras Reservoir, which holds 31 billion gallons, to up to 94 billion gallons as deferred. The capital plan adopted on February 10, 2026 deprioritized all but one regional alternative supply project: PureWater Peninsula, projected at 6 to 12 million gallons a day, stays in planning, with construction deferred to about FY2035-36.
The state's turn
On October 29, 2026 the State Water Resources Control Board adopted an updated Bay-Delta Plan for the Sacramento River and the Delta. Flow requirements for the Tuolumne River, the source of Hetch Hetchy water, are still pending.
What the report adds
How the supply chain, the 27 wholesale cities and agencies, wastewater and governance fit together, and where the adopted plan concentrates spending, are set out in the full report. The full report, Water Systems Overview: San Francisco Public Utilities Commission, is available for USD 499. For a free overview, read the San Francisco Public Utilities Commission Utility Snapshot.