Sweetwater Authority pumps groundwater from two sources, the Sweetwater Alluvium and the San Diego Groundwater Formation.
National City Wells
At its National City Wells, the Authority obtains fresh water from the San Diego Formation, approximately 800 feet below the surface. Formation water is naturally filtered by the earth, but is disinfected and tested to ensure that it is safe to drink.
Reynolds Groundwater Desalination Facility
At its Reynolds Groundwater Desalination Facility in Chula Vista, the Authority extracts brackish water from the alluvium of the Sweetwater River, and from the San Diego Formation. Brackish water contains high levels of dissolved solids, which are removed at the facility with advanced reverse osmosis membrane treatment.