As Southern California faces the worst drought on record in 1,200 years, water is at the forefront of the minds of many. Some communities are facing water restrictions imposed by cities and utility companies. Many are asking, “why?”

The Water Replenishment District (WRD) manages southern Los Angeles County’s groundwater supply. That’s billions of gallons of fresh water held in naturally formed underground aquifers. Groundwater provides nearly half of the drinking water supply for more than 4 million residents, or 11% of California’s population. The other half is imported from the Sacramento Delta and the Colorado River hundreds of miles away.

Drought conditions and climate change have reduced the amount of water that can be imported to Southern California. The good news is WRD has been preparing for climate change and extreme drought conditions through groundwater replenishment by increasing the use of recycled wastewater.

WRD was established by a vote of the people in 1959 to address the groundwater overdraft through replenishment. At its inception, WRD’s water supply for replenishment was 100% imported. This year, WRD celebrates 60 years of using recycled water to replenish the basins.

Through innovative planning, WRD and regional partners produce enough water to meet 100% of groundwater replenishment needs at its conservation facilities (also known as the spreading grounds) to eliminate the need for increasingly scarce imported water from the Sacramento Delta and the Colorado River. WRD reached this monumental goal three years ago thanks to its Water Independence Now (WIN) program and its regional partners, which include West Basin Municipal Water District, Central Basin Municipal Water District, Metropolitan Water District, Los Angeles Department of Water and Power, the Bureau of Sanitation, and LA County Sanitation Districts.

Building on WIN’s success, WRD has set a loftier goal—“WIN 4 All.” Today, WRD is working with its regional partners to increase the supply of recycled water and store it in aquifers. The goal is to completely eliminate the need for any imported water in the region.

“The key to a sustainable drought-proof water future lies under our feet,” said Director Rob Katherman, who represents the South Bay on the WRD board of directors. “Though we can’t see them, groundwater aquifers are an immense natural underground reservoir – currently with empty storage space that can hold nearly 150 billion gallons of water. WRD is working with our regional water agencies to fill that storage space with reclaimed water that can be used during dry years.”

WRD Converts Brackish (Salty Groundwater) to Drinking Water

One of the biggest “WIN 4 All” projects is WRD’s Regional Brackish Water Reclamation Program (RBWRP). Beneath the South Bay are billions of gallons of brackish groundwater. Brackish Water is water occurring in the natural environment that has more salinity than freshwater, but not as much as seawater. The condition is caused by seawater intrusion due to over-pumping during the first half of the 20th century prior to the construction of the West Coast Seawater Barrier built in the 1950s. WRD plans to extract, desalinate and purify this water. The result will be a new source of drinking water for the South Bay.

Through RBWRP, WRD will desalt this brackish water and create new space in the aquifer to store fresh water for future use. The process will produce up to 10 million gallons of fresh water a day using reverse osmosis to treat the salty water so it may be used as drinking water.

WRD has a successful track record with groundwater desalination projects. The WRD Robert W. Goldsworthy Desalter located in the City of Torrance was commissioned in 2001 and expanded in 2018. The facility treats up to 5 million gallons per day of brackish groundwater, which is put directly into the City of Torrance potable water system.

The RBWRP will build on this success to create a new supply of “drought-proof” water. Even during dry years, this water will be available to be extracted, treated, and made available to water suppliers in the South Bay. This water will help reduce the region’s need for imported water. It will also help us to plan for a more drought-resilient future and ensure we’re more prepared for challenges that climate change may bring. Learn more at ∙

Tour WRD’s State-of-the-Art Water Treatment Facility

The Water Replenishment District offers a variety of engaging tours that teach about groundwater replenishment and basin management. Currently, WRD offers virtual and limited in-person tours of its newest advanced water treatment facility, the Albert Robles Center (ARC) for Water Recycling and Environmental Learning (ARC), located in Pico Rivera.

The ARC facility encompasses an advanced water treatment facility, a fully digital learning center and water-efficient demonstration gardens. To learn more about these tours, visit