California water

California water has three sources:

• Central Valley Project
• State Water Project based mostly on northern sources such as the Sierra Nevada mountains
• the Colorado River and the federal system based on that
• local reservoirs and streams
• groundwater such as wells

The state-based Sierra Nevada system supplies 30% of Southern California's water supply. The Colorado River supplies a substantial but smaller percentage, based on a federal system.

California takes an unfair priority over Arizona for water from the Colorado River, due to favoritism suspected of Herbert Hoover when he negotiated the original deal a century ago.