Water Sources

The Los Angeles County Waterworks Districts (LACWD), a division of the County of Los Angeles Department of Public Works, provides customers with water from three sources: local groundwater and water imported through the State Water Project (SWP) and the Colorado River Aqueduct (CRA).

The State Water Project is a system of reservoirs, pump stations, storage facilities, power plants, and 660 miles of pipes and canals that spans two-thirds the length of California. LACWD purchases imported water from local SWP contractors including Antelope Valley-East Kern Water Agency, Castaic Lake Water Agency and Metropolitan Water District of Southern California, or regional wholesale water agencies such as Los Angeles Department of Water and Power and West Basin Municipal Water District.

The majority of the water in the SWP is collected as runoff and snowmelt from Northern California and the Sierra Nevada Mountains. While the source water is very pure, it collects sediments and organics along the way and must be treated before it is delivered for human consumption. The imported water is generally treated using conventional treatment methods including coagulation, flocculation, sedimentation, filtration, and disinfection.

SWP contractors request a certain amount of SWP water annually. The maximum allocation a contractor can receive in any year is called their Table A amount. On average, studies have shown that contractors receive about 60% of their Table A amount each year. Reliability in the SWP is very difficult to predict and can vary greatly year to year due to changing weather conditions and environmental impacts that can result in pumping restrictions.

The Colorado River Aqueduct stretches 240 miles from Lake Havasu on the California-Arizona border to Lake Mathews in Riverside County. California has been taking over 5 million acre feet of water from the Colorado River a year even though they are only entitled to 4.4 million acre feet. The Metropolitan Water District is a consortium of 26 cities and water districts that imports water from the SWP and CRA to supply drinking water to much of Southern California. In areas where local groundwater is available, LACWD owns and operates groundwater production wells which are used to pump the water from the groundwater basin to the surface. The groundwater is then disinfected and pumped into the distribution system.

Los Angeles County Waterworks Districts

District No. 21 – Kagel Canyon

District No. 21 serves approximately 250 customers, and receives its water through an interagency agreement with the Cities of Glendale and Los Angeles. The City of Glendale provides groundwater to the City of Los Angeles in exchange for the City of Los Angeles providing District No. 21 with a connection to their water system which is located at the south end of the District. The City of Los Angeles’ water is a mixture of groundwater pumped from the local area, treated State Water Project water, and water that is imported by the City of Los Angeles from the Owens Valley.

District No. 40 – Antelope Valley

The largest district, District No. 40 serves approximately 54,000 customers with water that is imported to the Antelope Valley through the State Water Project and then treated at AVEK’s Quartz Hill Water Treatment Plant and Eastside Water Treatment Plant. This supply is supplemented by groundwater pumped from the Antelope Valley Groundwater Basin by approximately 50 wells owned and operated by the District

In an effort to ensure supply reliability, District No. 40 is undertaking projects to store excess imported water in the ground during wet years so that it can be extracted and used during dry years. District No. 40 has designed many of its groundwater wells so that excess treated imported water in the District’s distribution system can be injected through the wells and stored until a future time when it is needed. This program is called aquifer storage and recovery (ASR). District No. 40 is also working with AVEK to utilize large undeveloped areas in the Antelope Valley to deliver imported water and allow it to infiltrate into the ground where it will be stored. Subsequently, new wells will extract this water at a later time when it is needed.

District No. 40 also has an agreement with the Los Angeles County Sanitation Districts to use over 13,000 acre-feet of highly treated wastewater produced at their Palmdale and Lancaster Water Reclamation Plants on the North Los Angeles County Regional Recycled Water Project. This “recycled water” will be made available through construction of a completely separate water distribution system for irrigation and other applications that do not require the water to be drinkable. This project will decrease the region’s reliance on imported water and local groundwater supplies.

District No. 36 – Val Verde

District No. 36 is served with imported State Water Project water that is treated at Castaic Lake Water Agency’s Earl Schmidt Filtration Plant and Rio Vista Water Treatment Plant. The District also utilizes groundwater from the Saugus formation beneath the District service area. In general, the supply in the District is made up of 50% imported water and 50% groundwater. District No. 36 serves approximately 1,300 customers.

District No. 37 – Acton

The water supply for District No. 37 is primarily groundwater pumped from 3 wells owned and operated by the District. The groundwater is supplemented by imported water from the State Water Project which is treated at AVEK’s Acton Water Treatment Plant. District No. 37 serves approximately 1,400 customers.

District No. 29 – Malibu (Including Marina del Rey Water System)

District No. 29 serves over 7000 customers using imported water from the State Water Project and the Colorado River Aqueduct. The water is initially treated to drinking water standards at one of Metropolitan Water Districts’ water treatment plants. District No. 29 receives the water through a contract with the West Basin Municipal Water District, a member agency of the Metropolitan Water District. The District’s connection to Metropolitan Water District’s system is located in Culver City. The water travels to the District through a 35-mile transmission main in Pacific Coast Highway.

Maps of all the districts are available here.

The following agencies provide SWP water to our service areas: