East Bay Municipal Utility District's water rights allow it to divert about 364,000 acre-feet a year from the Mokelumne River, yet its annual production stayed below 190,000 acre-feet in every year from FY 2016 to FY 2025. On paper the District has room to spare; in practice, the binding limits are seniority, river flows and one conveyance corridor.
Others drink first
Senior and other prior rights come ahead of the District. Woodbridge Irrigation District is entitled to 60,000 acre-feet when inflow to Pardee is at least 375,000 acre-feet, and 39,000 acre-feet otherwise. Amador County diverters may take up to 20,000 acre-feet and Calaveras County diverters up to 27,000 acre-feet a year, and Camanche releases for fish follow a 1998 settlement. Runoff swings widely: about 224,000 acre-feet in Water Year 2021 and 1.929 million acre-feet in Water Year 2017.
One corridor
About 90% of the District's supply moves through three Mokelumne Aqueducts built in 1927, 1942 and 1963. They run about 83 miles, with about 10 miles above ground across the Delta, and carry 200 MGD by gravity or about 325 MGD with pumping. Interconnections on both sides of the Delta and local reservoirs holding up to six months of supply at 25% rationing are the fallback. Relining and recoating are planned for 2029–2032, and a deep tunnel under the Delta remains under consideration.
A comfortable 2026
Total system storage stood at 624,310 acre-feet on March 1, 2026, 81% of capacity, and at 684,000 acre-feet on April 15. The Board declared 2026 supply sufficient on April 28, 2026.
How the District's dry-year imports, transfers and groundwater plans fill the gap in a multi-year drought, how the state's new Bay-Delta Plan could change Mokelumne releases, and who governs each part of the system are examined in the report. The full report, Water Systems Overview: East Bay Municipal Utility District, is available for USD 499. For a free overview, read the East Bay Municipal Utility District Utility Snapshot.