Pure Water Oceanside Builds Indirect Potable Water Reuse Plant in San Diego: It Reduces Potable Water Imports into the City of Oceanside, California and Helps Recharge the Aquifer

     Phase One of Pure Water Oceanside’s indirect potable water reuse plant is up and running, reducing the share of water imported into the city from 89% to 67%. Phase Two will further reduce imports to 44%. The plant, backed by a $71 million investment, treats local wastewater and transforms it into clean drinking water.

     According to San Diego Red:

“Known as Pure Water Oceanside, the program is the first of its kind in the county. It utilizes treated water from the San Luis Rey Water Recovery Facility, subjecting it to ultrafiltration, reverse osmosis, and advanced ultraviolet oxidation. The purified water is then injected into the Mission Basin aquifer, before being extracted for final treatment and distribution as clean drinking water. This process is classified as indirect potable reuse.”

     The facility currently treats 4.5 million gallons per day with plans to increase that to 6 million gallons per day.

“Oceanside also manages the “La Salina” plant, built in 1949 and recognized as the city’s oldest wastewater treatment facility, which provides secondary treatment prior to ocean discharge. Meanwhile, the San Luis Rey facility continues to produce recycled water for urban landscaping, parks, and golf courses, and it’s the primary source for the Pure Water initiative.”

     Importing drinking water is costly and energy intensive. The local Mission Basin Aquifer has faced depletion, and recharging it with treated wastewater allows for further natural treatment in the aquifer. Water drawn from the aquifer is treated as well to meet drinking water standards.

     The company’s website explains the difference between recycled or reclaimed water and purified water. Recycled/reclaimed water undergoes some treatment and is reused for certain non-potable purposes like agriculture, industrial use, and landscaping. Purified water undergoes several additional purification steps. Oceanside makes this ultra-purified water.

 

 

  

References:

 

San Diego County’s first potable reuse plant: Pure Water Oceanside. Eric Sanchez. San Diego Red. October 3, 2026. San Diego County’s first potable reuse plant: Pure Water Oceanside

Pure Water Oceanside. Website. Pure Water Oceanside | Oceanside, CA

The Difference Between Recycled/Reclaimed Water and Purified Water. Oceanside. The Difference Between Recycled/Reclaimed Water and Purified Water | Oceanside, CA