Timeline Highlights | Timeline |
Before the formation of the West Basin Municipal Water District, coastal Los Angeles leaders and community members found there was a need for a public entity dedicated to managing and protecting local water supplies.
As a result, West Basin was formed in 1947 with the task of making local water supplies more reliable by seeking new water sources and protecting groundwater supplies through reduced pumping. Since then, the District has been delivering on its mission of water reliability and establishing drought resiliency through balanced and cost-effective water supply diversification.
In 2022, West Basin celebrated more than seven decades of water reliability and commemorated key moments in its history in recognition of this major milestone.
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Cool Timeline

1854 | First water wells drilled in the West Basin. |
1918 | Salt water intrudes into coastal aquifers in Redondo Beach area. |
1922 | Groundwater drops below sea level, salt water intrudes into drinking water wells in El Segundo. |
1931 | Following approval of a $220 million dollar bond, Colorado River Aqueduct construction begins. |
1940s | Industry increases pumping for World War II. |
1940 | Redondo Beach High School – salt water contaminates groundwater well. |
1940s | Planning for State Water Project begins. |
1941 | Colorado River Aqueduct is complete. |
1942-1944 | West Basin Survey Committee formed to determine salt water damage to the groundwater supply. |
1944-1945 | Production is 69,476 acre feet a year. |
1945 | West Basin Groundwater Conservation Group (WBGCG) formed by representatives from cities, private water utilities and local industries. |
1945 | WBGCG releases report showing more water being withdrawn from groundwater basin than being naturally replenished and overdraft is 29,000 acre feet. Suggested corrective measures include reduce the overdraft of groundwater, educating the public about the water shortage problem and finding a source of supplemental water, including reclaiming water from the San Fernando Valley and the Owens Valley. |
1946 | Legal action taken to arbitrate water rights and control overdraft in California Water Service Company, et al. v. Compton, et al., L.A. County Superior Court, Case # 506,806. |
1946 | West Basin Water Association organizes and initiates study under Harold Conkling to determine supplemental water source needed to prevent overdraft of groundwater supplies. Conkling’s report recommends the use of Colorado River water as supplemental supply. West Basin needs majority of public to vote in support of its formation as a Municipal Water District and become member of Metropolitan Water District of Southern California (MWD). |
1947 | Mayors of five South Bay cities form the South Bay Water Committee.
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1948 | U.S. Geological Survey releases water supply report showing fresh groundwater is threatened by salt water intrusion.
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1949 | Report on reclamation is prepared for L.A. County Board of Supervisors, outlining opportunities for using reclaimed water.
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1950 | In an effort to control salt water intrusion and determine effectiveness of maintaining a fresh water pressure ridge along the coast, County Flood Control begins fresh water injection tests into abandoned water well in Manhattan Beach.
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1951 | Legislature amends the County Flood Control District Act to authorize establishment of conservation zones.
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1952 | Report of Referee in West Basin adjudication is filed with the Court, ordering water producers to reduce groundwater extractions, requiring purchase of supplemental water to offset reduced pumping.
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1953 | Test barrier, paralleling Manhattan/Hermosa Beach area, development begins.
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1954 | Zone II is established to carry on barrier testing started by the State. |
1955 | Forty-six major groundwater producers in the West Basin voluntarily agree to restrain their groundwater extractions to 56,963 acre feet per year.
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1956 | Second adjudication action filed to gain jurisdiction over new producers and those who may have been overlooked during the service of the original action. Court orders continuation of the West Basin Reference to update physical facts and directs State Water Rights Board to make these determinations. |
1958 | Second report was prepared for the County Board of Supervisors, affirming findings of first report from 1949. It proposes construction and operation of water reclamation plant at Whittier Narrows to demonstrate the feasibility of wastewater reclamation. |
1959 | Central and West Basin Water Replenishment District is formed to purchase supplemental water to replenish the depleted groundwater basins. |
1959 | Construction begins on State Water Project. |

1960 | Draft of Continued Reference Report on West Basin Adjudication is filed with the Superior Court and recommends limiting groundwater production, providing exchange for water pool, appointing a Watermaster to administer the terms and conditions of the Court, and continued jurisdiction by the Court over this Action. |
1961 | Aqueduct expansion complete, bringing imported water delivery capacity to 1,180,000 acre feet annually. Court enters judgment in the original West Basin adjudication requiring groundwater production to be reduced to 64,042 acre feet. |
1963 | Development of test barrier paralleling the coast of Manhattan/Hermosa Beach is complete. |
1966 | Court enters second judgment against additional West Basin pumpers overlooked in first Action. All were made party to the terms of the original Judgment and the annual pumping was adjusted to 64,468 acre feet. Work begins on the Dominguez Gap Barrier Project to protect lower fresh water aquifers in the southeast area of the West Coast Basin from salt water intrusion. |
1968 | Flood Control District completes West Coast Basin Seawater Barrier consisting of 94 recharge wells injecting 50 million gallons of fresh water daily and 256 observation wells protecting groundwater supplies from salt water intrusion.
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1971 | Dominguez Gap Barrier Project begins, consisting of 29 injection wells. |
1972 | Special water conservation area operated by the County Flood Control District for West Coast Basin ends. Entire cost of financing barrier injection programs hereafter must be supported by the water pumpers.
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1973 | To prevent salt water intrusion at the southern end the County Flood Control District, additional facilities are recommended for West Coast Seawater Basin Barrier Project.
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1974 | Metropolitan Water District commences delivery of State Water Project in lieu of the Colorado River to West Basin for injection into seawater barriers.
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1975 | Eleven new injection wells complete in West Coast Basin Seawater Barrier Project, bringing total number of injection wells to 105. |
1976 | In FY 1975-76, West Basin Municipal Water District purchases 168,555 acre feet of water from Metropolitan Water District.
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1987-1992 | California experiences one of its most serious droughts in history. |
1988 | Congress enacts Federal Disaster Assistance Act of 1988, due to extent and severity of drought.
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1989 | Ten million people under drought-induced water rationing or conservations programs. |
1990 – 1996 | Rich Atwater joins West and Central Basins as General Manager. |
1991 | West Basin and City of Los Angeles reach agreement to deliver treated sewer water from the City’s Hyperion plant to a new West Basin Water Recycling Facility in El Segundo. |
1994 | West Basin/Hyperion Pump Station is built to pump water to facility. |
1995 | West Basin Water Recycling Facility construction complete, delivering water to first customer, El Segundo Lakes golf course.
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1996 | West Basin Water Recycling Facility visitor’s center is complete.
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1997 | Phase II Water Recycling Facility complete, expanding production capacity of tertiary and barrier water. |
1998 | West Basin hosts first Water Harvest festival at the Water Recycling Facility. Hollywood Park in Inglewood is 100th recycled water customer. |
1999 | West Basin increases percentage of near-distilled quality sewer water injected into the seawater barrier from 25 to 50 percent.
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2000 | Phase III of the Water Recycling Facility expands capacity of microfiltration and reverse osmosis. |
2004 | Department of Water Resources awards West Basin $9 million Proposition 13 grant for expansion of its water recycling facilities.
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2005 | West Basin’s Water Recycling Facility celebrates 10th anniversary and the following achievements:
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2006 | West Basin adopts Conservation Master Plan as a guide for regional investments and translates conservation goals into tangible initiatives for residents, businesses and various levels of government.
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2006 | West Basin celebrates its 60th anniversary and renames its water recycling facility after long-time Director Edward C. Little. |
2007 | Construction complete on Phase IV Expansion, increasing recycled water production by 15 million gallons a day. |
2008 | West Basin produces its 100 billionth gallon of recycled water. |
2009 | West Basin and Water Replenishment District sign agreement to serve 100% purified recycled water to the West Coast Barrier. |
2010 | West Basin reaches 350 recycled water customer connections. |
2012-2016 | California declares a statewide drought emergency. |
2013 | Phase V expansion is completed to increase recycled water injected into the Barrier with the goal of achieving 100 percent recycled water injection and providing a more reliable, high-quality source of water to the aquifer. |
2018 | West Basin produces its 200 billionth gallon of recycled water. |
2019 | West Basin Director Gloria D. Gray begins serving two-year term as chairwoman of the Metropolitan Water District of Southern California’s Board of Directors. |
2019 | The Edward C. Little Water Recycling Facility Water Education Center is re-dedicated after undergoing major improvements. |
2019 | California adopts AB 1668 and SB 606, which set permanent water-consumption goals to prepare for future droughts and climate change, effective January 2019.
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2019 | Colorado River users agreed on a Drought Contingency Plan to address dwindling reservoir levels and enable the negotiation of long-term solutions to challenges on the river. |

2020 | West Basin celebrates its 25th year of recycled water innovation, producing more than 225 billion gallons of recycled water since 1995.
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2020 | West Basin announces its first delivery of recycled water to SoFi Stadium and Hollywood Park, home of the Los Angeles Rams and Los Angeles Chargers, in the city of Inglewood. This project provides 26 million gallons of recycled water per year, saving an equal amount of drinking water for the region. |
2021 | West Basin Board of Directors approves the District’s 2020 Urban Water Management Plan (UWMP), a strategic water resources planning guide that demonstrates West Basin’s ability to provide reliable water supplies to the region for the next 25 years. |
2021-Present | California declares a statewide drought emergency.
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2021 | West Basin Director Gloria D. Gray begins second two-year term as chairwoman of the Metropolitan Board of Directors. |
2022 | State Water Resources Control Board declares an emergency regulation to promote water conservation. |
2022 | Recycled Water Master Plan is finalized to help the District plan for the next chapter of its successful recycled water program.
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2022 | West Basin celebrates the 75th anniversary of its formation and the following achievements:
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