California’s water systems move water supply from places of abundance to places of need, and from wet years to dry ones.
These water systems are often categorized into three groups – Local Water Suppliers, the State Water Project, and the Federal Water Systems
California’s network of reservoirs, canals, and pumping stations form the backbone of our water supply systems.
Local and regional water suppliers are responsible for ensuring that water is supplied to homes, businesses, farms and other customers. These local and regional water suppliers operate networks of storage and delivery systems that are adapted to local needs.
Most irrigated farms in California receive water through their local irrigation district.
California’s State Water Project (SWP) provides drinking water to approximately 25 million residents, and provides water that helps to irrigate approximately 600,000 acres of farmland. 
The SWP is operated to improve water quality in the Sacramento-San Joaquin Rivers Delta, control flood risks on the Feather River, as well as provide recreation opportunities while enhancing fish and wildlife habitat.
The SWP stores water in 34 reservoir facilities in the state for delivery through approximately 700 miles of SWP canals and pipes, including the California aqueduct.
Additionally, the project generates electrical energy using 5 hydroelectric plants and 4 pump-generator plants.
Learn more about the State Water Project.
The United States government has developed several water storage and delivery systems in California.
Central Valley Project
The Central Valley Project (CVP) is one of the nation’s major water developments. The CVP extends approximately 400 miles, from the far northern portions of the state to the Kern River plain in the South. The CVP provides water for farms, communities, and wildlife users. The Central Valley Project manages nearly 500 miles of major canals, tunnels, and other conduits, as well as 20 reservoirs, and 11 power plants. Learn more about the CVP.
Lower Colorado River Facilities
The Lower Colorado River Facilities complex includes some of the most well-known water facilities in the nation, including Hoover Dam. The Lower Colorado River facilities provide water in five states, Arizona, California, Nevada, New Mexico, and Utah. Water stored in these facilities is also shared with the nation of Mexico. Learn more about the Lower Colorado River facilities complex.
Much of California’s water supply system was designed and built more than 50 years ago. Over the years California’s population has grown and the system that was designed to provide water to 20 million people simply can’t keep up with a population that is almost double that today.
In order to meet our future needs California must invest in additional conservation and recycling as well as new supplies that can be stored in reservoirs or groundwater aquifers and moved efficiently to parts of the state where they are needed.