Water and Drought

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Water

California’s water system is complex. This complexity can be seen in how the system is structured—with multiple sources of water that are interconnected in various ways. It is also evident in how the system is financed—using a variety of sources at the local, state, and federal level to meet the needs of urban and agricultural water users and the environment. This web page provides some "quick reference" tables and graphics that illustrate some key elements of California's water system.

On this page:

History and Management
Precipitation and Water Use
Floods
Groundwater
State Bond Funding

HISTORY AND MANAGEMENT

Selected Events in State Water Policy History—Timeline

Selected Events in State Water Policy--A Timeline

Many Entities Are Involved in Water Management

	Responsibilities
	Water Supply	Water Quality	Flood Control
State Agencies
Department of Water Resources	X		X
State Water Resources Control Board	X	X
California Public Utilities Commission	X	X
Colorado River Board	X
Delta Stewardship Council	X	X	X
Department of Pesticide Regulation		X
Department of Toxic Substances Control		X
Department of Conservation		X
Office of Environmental Health Hazard Assessment		X
Federal Agencies
Bureau of Reclamation	X		X
Army Corps of Engineers	X		X
Environmental Protection Agency		X
Geological Survey	X	X
Other Entities
Cities and counties	X	X	X
Special districts	X	X	X
Tribal governments	X	X	X
Private water companies	X

For more information, please see our publication California’s Water: An LAO Primer

California's Water System Moves Water, Mainly from North to South

For more information, please see our publication Achieving State Goals for the Sacramento-San Joaquin Delta

Types of Water Systems in California

Public Water System: Provides water for human consumption and (1) has 15 or more service connections or (2) regularly serves at least 25 individuals daily at least 60 days out of the year. Water quality is generally regulated by the State Water Resources Control Board (SWRCB), although in 29 counties SWRCB has delegated authority to regulate smaller systems with between 15 and 200 connections to county environmental health departments.

Community Water System: Public water system that (1) serves at least 15 service connections used by yearlong residents or (2) regularly serves at least 25 yearlong residents. Roughly 2,900 across the state, serving about 39 million people.

Noncommunity Water System: Public water system that (1) regularly serves 25 or more of the same persons for more than 6 months but fewer than 12 months per year (referred to as “nontransient”), such as a school, or (2) does not regularly serve at least 25 of the same persons over 6 months of the year (referred to as “transient”), such as a rest stop or campground. Roughly 1,500 nontransient systems and 3,000 transient systems across the state.

Tribal Water System: Public water system that is located on tribal land and serves a federally recognized tribe. Regulated under tribal sovereign authority in partnership with the U.S. Environmental Protection Agency, not SWRCB.

State Small Water System: Provides water for human consumption with between 5 and 14 service connections and does not regularly serve drinking water to more than an average of 25 individuals daily for more than 60 days out of the year. Water quality is overseen by county health officers. Roughly 1,500 across the state.

Domestic Well: Groundwater well used to supply water for the domestic needs of an individual residence or a water system that has no more than four service connections. Water quality not regularly monitored by the state or local governments. At least 350,000 across the state, providing water for between 1.5 million and 2.5 million Californians.

For more information, please see our publication Expanding Access to Safe and Affordable Drinking Water in California—A Status Update.

PRECIPITATION AND WATER USE

California's Precipitation is Highly Variable

Water Supply Versus Demand

Use of Water Changes Significantly From Wet to Dry Years

For more information, please see our publication California’s Water: An LAO Primer

FLOODS

Exposure to 500-Year Flood by Region

Illustration of Key Flood Infrastructure Components

For more information, please see our publication Managing Floods in California

GROUNDWATER

Implementation Timeline for Major Sustainable Groundwater Management Act (SGMA) Requirements

STATE BOND FUNDING

Water-Related General Obligation Bonds

1970-2018 (In Millions)

Year	Proposition Number	Title	Amount Authorized
1970	1	Clean Water Bond Law of 1970	$250
1974	2	Clean Water Bond Law of 1974	250
1976	3	California Safe Drinking Water Bond Law of 1976	175
1978	2	Clean Water and Water Conservation Bond Law of 1978	375
1982	4	Lake Tahoe Acquisitions Bond Act	85
1984	2	California Safe Drinking Water Bond Law of 1984	75
1984	28	Clean Water Bond Law of 1984	325
1984	19	Fish and Wildlife Habitat Enhancement of 1984	85
1986	55	California Safe Drinking Water Bond Law of 1986	100
1986	44	Water Conservation and Water Quality Bond Law of 1986	150
1988	8	California Safe Drinking Water Bond Law of 1986	75
1988	70	California Wildlife, Coastal, and Park Land Conservation Act	776
1988	83	Clean Water and Water Reclamation Bond Law of 1988	65
1988	82	Water Conservation Bond Law of 1988	60
1996	204	Safe, Clean Reliable Water Supply Act	995
2000	13	Safe Drinking Water, Clean Water, Watershed Protection, and Flood Protection Act	1,970
2000	12	Safe Neighborhood Parks, Clean Water, Clean Air, and Coastal Protection Bond act of 2000	2,100
2002	40	California Clean Water, Clean Air, Safe Neighborhood Parks, and Coastal Protection Act of 2002	2,600
2002	50	Water Security ,Clean Drinking Water, Coastal and Beach Protection Act of 2002	3,440
2006	1E	Disaster Preparedness and Flood Protection Bond Act of 2006	4,090
2006	84	Safe Drinking Water, Water Quality and Supply, Flood Control, River and Coastal Protection Bond Act of 2006	5,388
2014	1	Water Quality, Supply, and Infrastructure Improvement Act of 2014	7,120a
2018	68	Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access for All Act of 2018	4,100
Total			$34,649
aProposition 1 also repurposed a total of $425 million from Proposition 84, Proposition 1E, Proposition 50, Proposition 13, Proposition 204, and Proposition 44.

For more information, please see the California Natural Resources Agency's bond accountability webpage.

Last Updated: December 2021

LAO Staff Contacts

Sonja Petek: (916) 319-8340; Water, Coastal Development, and Fish and Wildlife