East Bay Municipal Utility District

In 1923, EBMUD was founded due to the rapid population growth and severe drought in the area. The district constructed Pardee Dam (finished in 1929) on the Mokelumne River in the Sierra Nevada, and a large steel pipe Mokelumne Aqueduct to transport the water from Pardee Reservoir across the Central Valley to the San Pablo Reservoir located in the hills of the East Bay region. In subsequent years, EBMUD constructed two additional aqueducts to distribute water to several other East Bay reservoirs. From the various large regional reservoirs, water is transported to treatment plants and delivered to local reservoirs and tanks, thence distributed by gravity to customers.

In the 1980s with federal grant funding, EBMUD undertook a major facility expansion to accommodate wet weather waste water overflow (i.e. the vastly increased system demand in the rainy season). This project took many years of construction for implementation, after the planning and Environmental Impact Statement phases.

In 1994, the EBMUD board of directors approved the Seismic Improvement Plan (SIP), a $189 million capital project designed to minimize damage and disruption in the event of a potential earthquake along the Hayward Fault. One of EBMUD's main water supply lines, the Claremont Tunnel, traverses the Hayward Fault, and the maximum credible earthquake along the fault could sever the tunnel, which was originally built in 1929. Some of the major projects included in SIP were the Southern Loop Pipeline, a new 11-mile (18 km) seismically-reinforced alternate route which would allow restoration of water service; and seismic upgrades to the Claremont Tunnel. The expected benefit of SIP was avoiding a potential $1.2 billion in lost revenue and damage resulting from a major earthquake.

In May 2008, EBMUD announced severe drought and austerity measures for its customers. With the easing of the drought, these measures were rescinded in 2010. EBMUD announced mandatory water rationing again in August 2014. The emergency regulations imposed during this prolonged drought were relaxed effective July 1, 2016, after the drought was declared officially ended. EBMUD announced mandatory water rationing again in April 2022, following a bleak California snow survey and the driest January to March period on record.