Students know the source of the water used by their local communities.

The origin of the fresh water flowing into your house depends on where you live in California. Your home’s water probably traveled hundreds of miles through man-made aqueducts and reservoirs. However, for many rural residents, it may come directly from a backyard well or a local stream.

In California, two-thirds of the fresh water in the state is found in the northern part of the state. However, most people live in the southern part of the state where two-thirds of the water is needed. California’s climate causes another imbalance in supply and demand. Almost all the precipitation occurs in the winter, and the greatest demand for water occurs in the summer. Much of the winter precipitation occurs as snow that falls and accumulates in the mountains. This water is collected for human use when snowmelt fills mountain rivers, lakes, and reservoirs.

Because of these two imbalances in water supply and need, water needs to be shipped from the north to the south, and it needs to be collected in the winter and spring for use throughout the year. The State Water Project, overseen by the California Department of Water Resources, manages this collecting and distributing of state water. The runoff from rainfall and snowmelt is captured in reservoirs in the north and transported via a system of canals, aqueducts, and pumping stations to areas without abundant water supplies. To accomplish this mission, the State Water Project uses 32 storage facilities, reservoirs, and lakes; 17 pumping plants; 5 power plants; and 660 miles of aqueducts and canals.

Groundwater is another important source of water. While people usually think of wells as serving an individual home or farm, large wells are often drilled below the water table to pump water to be used by towns and even cities such as Fresno.

California also uses a lot of water from the Colorado River which flows through Colorado, Utah, Arizona, Nevada, and California. The state must negotiate its use of Colorado River water with these other states and with the federal government. Due to drought and population growth in the Southwest, California must reduce its use of Colorado River water.

A good way to research the source of local fresh water is to check the local utility, the company that supplies water to your community. If you pay for water, check the water bill for appropriate contact information.

We have also provided below some general information for different parts of California as well as links to useful websites:

You may be able to find the name of your local water agency and a link to their website through the following page hosted by the Association of California Water Agencies.

http://www.acwanet.com/aboutacwa/acwamembers/publicagency.asp

SOUTHERN CALIFORNIA:

Twenty-six Southern California water agencies are members of the Metropolitan Water District (MWD). You can find contact information for most Southern California water agencies at

http://www.mwd.dst.ca.us/mwdh2o/pages/memberag/member02.html

The Metropolitan Water District (http://www.mwd.dst.ca.us) serves 18 million people in the southern part of the state, primarily by providing water to local utilities that then distribute to homes and businesses. The MWD gets most of its water from the State Water Project, which is primarily water that originally precipitated in Northern California as snow on the western side of the Sierra Nevada mountains. The MWD also gets about half that amount from the Colorado River.

The city of Los Angeles has its own Los Angeles Aqueduct System. This system, which delivers water from the Eastern Sierra Nevada mountains, provides about half of the city’s water needs. Most of the rest comes from the Metropolitan Water District. More information can be obtained from the Los Angeles Department of Water and Power:

http://www.ladwp.com/ladwp/areaHomeIndex.jsp?contentId=LADWP_WATER_SCID

The San Diego County Water Authority supplies up to 90% of the county’s water, and has 23 member agencies (such as Carlsbad, Del Mar, Otay, City of San Diego, and Vista). The vast majority of that water is imported, primarily purchased from the Metropolitan Water District. Check out information and links at

http://www.sdcwa.org/about/siteindex.phtml

CENTRAL CALIFORNIA:

Fresno gets its residential water from groundwater. More than 250 wells pump water from the aquifer. Rainfall and stream flow replace about half that water annually. Fresno Department of Public Utilities also takes surface water from Millerton Lake and Pine Flat Reservoir and pumps it underground to replenish the aquifer.

http://www.fresno.gov/public_utilities/water/water_information.asp

The Central Coast Water Authority distributes water for San Luis Obispo and Santa Barbara counties.

http://www.ccwa.com/members.htm

Sacramento gets 85% of its water from the Sacramento and American Rivers, and 15% from wells:

http://www.sacto.org/utilities/waterservices.html

SAN FRANCISCO BAY AREA:

In the San Francisco Bay Area, some fresh water comes from local sources in the form of rain runoff or groundwater, but the majority of water comes from snowmelt from the western slopes of the Sierra Nevada mountains. The Hetch-Hetchy Reservoir near Yosemite National Park supplies as much as 85% of Bay Area water. Here are some San Francisco Bay Area local utility websites:

San Francisco Public Utilities Commission
http://sfwater.org/main.cfm/MSC_ID/16

Alameda County Water District (ACWD)
http://www.acwd.org/acwd-sources.html

Contra Costa Water District (CCWD)
http://www.ccwater.com/welcome/profile.asp

East Bay Municipal Utility District (EBMUD)
http://www.ebmud.com/water_&_environment/water_supply/

Santa Clara Valley Water District (SCVWD)
http://www.valleywater.org/About_Us/District_Info/FAQs.shtm

NORTHERN CALIFORNIA

North of San Francisco and Sacramento, the local rivers, streams and groundwater are the likely sources of residential water. If you live in the far northern part of the state, your water may have even come from Oregon’s Klamath River. Check with the local utility for more information.

GENERAL INFORMATION

To learn more about water, including water sources, usage and terms, visit the United States Geologic Survey’s Water Science for Schools website at http://ga.water.usgs.gov/edu/index.html

To learn more about groundwater, visit the Groundwater Foundation Kid’s Corner http://www.groundwater.org/kc/whatis.html