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State Water Project


The State Water Project is just one of the sources of water supply Valley Water uses to deliver the water that comes out of your faucet. To reach many of us, water must travel long distances through complex delivery systems such as the California State Water Project (SWP). The SWP is the nation's largest state-built water and power development and conveyance system.

The SWP is a system of reservoirs, aqueducts, power plants and pumping plants. Its main purpose is to store water and distribute it to urban and agricultural water suppliers in Northern California, the San Francisco Bay Area, the San Joaquin Valley and Southern California. Approximately 70 percent of the contracted water supply goes to urban users and 30 percent goes to agricultural users. Other purposes of the SWP are to improve water quality in the Sacramento-San Joaquin River Delta, control Feather River flood waters, provide recreation, and enhance fish and wildlife.

Today, the SWP includes 34 storage facilities, reservoirs and lakes; 20 pumping plants; 4 pumping-generating plants; 5 hydroelectric power plants; and about 700 miles of open canals and pipelines. Planned, designed, constructed and now operated and maintained by the California Department of Water Resources (DWR), this unique facility provides water supplies for 27 million Californians and more than 750,000 acres of irrigated farmland.

In 1965 the SWP began delivering water to Santa Clara County. SWP water comes from Oroville Reservoir on the Feather River and flows through the Delta to Clifton Court Forebay, located in the southern Delta. Water is then pumped at the Harvey O. Banks Pumping Plant to Bethany Reservoir. From there, it is pumped at the South Bay Pumping Plant into the South Bay Aqueduct, regulated at Del Valle Reservoir if appropriate, and delivered at the northern end of Santa Clara County to the terminal tank at Santa Clara Valley Water District’s Penitencia Water Treatment Plant.

Valley Water has a contract for 100,000 acre-feet per year of water from the SWP. (One acre-foot is approximately the amount of water used by two families of five in one year.) Each year, water agencies that have contracts with the SWP are allocated a percentage of their contract amount depending on the amount of rain and snow, regulatory restrictions to protect fish and water quality, as well as other factors.

Between the years 2000 and 2022, Valley Water has only received 100% of its contract amount in one year, 2006. Valley Water's long-term average SWP supply is estimated to be about 60,000 AF of water from the SWP annually. Since 1994, all SWP contracts south of the Delta provide the same percentage allocation each year regardless of whether supplies are used for municipal and industrial (M&I) or irrigation purposes.

For more information regarding the State Water Project, visit the Department of Water Resources website.