State Water Project

Aerial photo of Sacramento-San Joaquin Delta

Aerial photo of Sacramento-San Joaquin Delta.

The California State Water Project (SWP) is a multi-purpose water storage and delivery system that extends more than 705 miles -- two-thirds the length of California. A collection of canals, pipelines, reservoirs, and hydroelectric power facilities delivers clean water to 27 million Californians, 750,000 acres of farmland, and businesses throughout our state.

Planned, built, operated and maintained by DWR, the SWP is the nation’s largest state-owned water and power generator and user-financed water system. The project is considered an engineering marvel that has helped fuel California’s population boom and economic prosperity since its initial construction.

The SWP was designed to deliver nearly 4.2 million acre-feet of water per year. Water is received by 29 long-term SWP Water Supply Contractors who distribute it to farms, homes, and industry. Today, about 30 percent of water from the SWP is currently used for irrigation, mostly in the San Joaquin Valley, and about 70 percent is used for residential, municipal and industrial use.

The State Water Project also plays an important role in efforts to combat climate change. Not only does it help California manage its water supply during extremes such as flooding and drought, it is also a major source of hydroelectric power deliveries for the State's power grid.

Benefits of the SWP:

The primary purpose of the SWP is water supply delivery and flood control, but it provides many additional benefits, including:

  • Power generation
  • Recreation activities
  • Environmental stewardship


Note: The first map below shows State Water Project contractors, reservoirs, conveyance systems, and power generation and pumping plants. Use your mouse to hover or click on designated locations or icons for additional details. You can also use the legends on the right side or bottom of the maps for navigating to specific locations. Zoom in to see labels and navigation points more clearly.
The map below shows reservoir storage and aqueduct flow data for the California State Water Project. All data used for this map comes from the California Data Exchange Center and should be considered preliminary data and subject to change. Please email if you have any questions regarding this data.
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