East Bay Municipal Utility District

East Bay Municipal Utility District
Company type	Public utility district
Industry	Water supply and wastewater treatment
Founded	1923
Headquarters	Oakland, United States
Area served	Eastern San Francisco Bay Area, including Alameda County and Contra Costa County
Products	Potable water supply, wastewater treatment

Adapted from the English Wikipedia article East Bay Municipal Utility District, available under CC BY-SA 4.0Updated 7 August 2025

East Bay Municipal Utility District (EBMUD), commonly referred to as "East Bay Mud," operates as a public utility district delivering water supply and wastewater treatment services throughout roughly service area in the eastern region of the San Francisco Bay Area. By 2018, EBMUD provided potable water to nearly 1.4 million individuals residing in sections of Alameda County and Contra Costa County, encompassing municipalities such as Richmond, Berkeley, Oakland, and San Leandro, among others. Its wastewater treatment operations serve approximately 685,000 residents within an 88-square-mile jurisdiction. With an annual population growth rate averaging 0.8%, EBMUD projects its customer base will reach 1.6 million by the year 2030.

Based in Oakland, EBMUD oversees critical infrastructure assets including two reservoirs on the Mokelumne River, five terminal reservoirs, of aqueducts for water transmission, of water distribution mains, six treatment facilities for potable water, of interceptor sewers for wastewater, and a regional wastewater treatment plant capable of processing up to 320 million gallons per day (MGD).

EBMUD Reservoirs

History

Established in 1923 during a period marked by rapid demographic expansion and drought conditions, EBMUD constructed the Pardee Dam (completed in 1929) on the Mokelumne River located in the Sierra Nevada. To convey water from Pardee Reservoir across the Central Valley to the East Bay hills’ San Pablo Reservoir, it built the steel Mokelumne Aqueduct. Subsequent aqueduct installations extended supply capabilities to additional East Bay reservoirs. Water sourced from these regional reservoirs undergoes treatment before being stored in local reservoirs and tanks, then distributed to customers primarily through gravity-fed systems.

During the 1980s, supported by federal funding, EBMUD expanded its infrastructure to better manage wet weather wastewater overflows caused by increased precipitation during rainy seasons. This extensive initiative involved multi-year planning and comprehensive environmental assessments.

In 1994, EBMUD authorized the $189 million Seismic Improvement Plan (SIP) aimed at mitigating earthquake hazards along the Hayward Fault. The plan featured construction of the Southern Loop Pipeline—a seismically strengthened alternative water conduit—and enhancements to the historic Claremont Tunnel (built in 1929), a vital supply line crossing the fault zone. The SIP was designed to avert potential losses estimated at $1.2 billion from seismic events.

EBMUD has enacted drought response measures on several occasions: initially imposing restrictions in May 2008 which were lifted by 2010; reintroducing mandatory rationing in August 2014 that eased by July 2016 after drought conditions subsided; and reinstating limitations in April 2022 due to unprecedented dry spells and unfavorable snowpack assessments.

Finances

The District contends with considerable unfunded liabilities, including $535 million related to pension obligations and $89 million associated with retiree healthcare costs. Revenue sources for EBMUD’s water supply and sewage treatment operations encompass water sales, hydroelectric power generation, system capacity charges, wastewater treatment fees, connection fees, charges for wet weather facility usage, interest income, and property tax increments.

In 2007 projections indicated that the water system would generate $375.5 million in total revenue. Water sales accounted for roughly 76% of this amount; System Capacity Charges contributed about 7%; Property Tax Revenue made up approximately 5%; while the remaining 12% derived from interest earnings, electric energy sales, reimbursements, and other miscellaneous sources.

Water rights

Nearly 90% of the water supplied by EBMUD is sourced from the safeguarded Mokelumne River watershed, which spans 577 square miles. The district possesses water entitlements allowing withdrawal of up to 325 million gallons daily, amounting to an annual allocation of 364,000 acre-feet. In typical years, East Bay reservoirs benefit from an additional 30,000 acre-feet of local runoff; however, during extreme drought conditions, these amounts fall short due to evaporation and other losses.

In February 2020, EBMUD became one of 75 recipients awarded permanent federal water contracts under the Central Valley Project, thereby enhancing the long-term stability of its water supply.

Effects of California drought

In April 2015, EBMUD declared a Stage 4 critical drought emergency and set a target to reduce water consumption across the community by 20%. To achieve this objective, the district introduced stricter water use regulations and augmented its supply with 33,250 acre-feet obtained from the Central Valley Project. Rigorous conservation efforts were implemented, with reservoir storage levels anticipated to range between 320,000 and 330,000 acre-feet by the end of that year.

By May 10, 2016, as reservoir volumes rose above average levels, EBMUD lifted the drought emergency declaration. The governing board eased numerous conservation restrictions and removed the 25% surcharge starting July 1, 2016. Pardee Reservoir reached full capacity in January 2017 and began releasing surplus water into Camanche Reservoir.

Future expansion

To address projected water demands for 2040, EBMUD evaluated the possibility of enlarging Pardee Reservoir through construction of a new dam. Environmental advocates opposed this proposal due to concerns over potential harm to well-loved recreational sites. Opponents encouraged EBMUD to collaborate with the consortium investigating expansion of the Los Vaqueros Reservoir, managed by the Contra Costa Water District (CCWD). Initially, EBMUD dismissed this alternative as insufficiently developed, whereas CCWD maintained that their plans were more advanced.

In 2009, environmental organizations filed a lawsuit challenging the Environmental Impact Statement (EIS) related to Pardee’s expansion. Following a two-year legal proceeding, Sacramento Superior Court Judge Timothy Frawley ruled in 2011 that EBMUD had inadequately addressed environmental consequences. The judgment cited failure to consider less damaging options such as partnering with CCWD on Los Vaqueros expansion. Additionally, it noted overlooked effects including flooding popular whitewater areas, destroying the historic Middle Bar Bridge, and submerging culturally important black willow habitats significant to the native Miwok community.

Subsequent to this ruling, EBMUD abandoned plans for a new dam on the Mokelumne River in December 2011 and committed to collaborating with CCWD on expanding Los Vaqueros Reservoir.

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