Orange County PFAS treatment facility begins operations

The Orange County Water District (OCWD; the District) and the Serrano Water District (Serrano) began operating one of the county’s first treatment plants to remove per-and polyfluoroalkyl substances (PFAS) from local well water.

PFAS are a group of thousands of manmade, heat-resistant chemicals that are prevalent in the environment and are commonly used in consumer products to repel water, grease and oil. Due to their prolonged use, PFAS are being detected in water sources throughout the United States, including the Orange County Groundwater Basin, which supplies 77 percent of the water supply to 2.5 million people in north and central Orange County. Despite playing no role in releasing PFAS into the environment, water providers must find ways to remove it from their local water supplies.

The Serrano facility is among 35 PFAS treatment facilities being designed and constructed in Orange County over the next two years; Serrano is one of the first in the county to be completed and go online. OCWD is funding 100 percent of design and construction costs and 50 percent of operation and maintenance costs for its water suppliers like Serrano.

“OCWD and our dedicated staff work tirelessly to address PFAS in the Orange County Groundwater Basin,” said OCWD President Steve Sheldon. “Recognizing the importance of being proactive and getting treatment facilities constructed swiftly, OCWD and its retail water providers like Serrano Water District are ensuring that Orange County’s water supply remains among the highest quality in the nation. I want to commend our team on achieving this milestone.”

Serrano, one of 19 water providers that pump water from the groundwater basin, had two of its groundwater wells impacted by perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), prompting it to temporarily shut down those wells and transition to purchasing imported water from the Colorado River and Northern California. These wells are among dozens of wells throughout Orange County that were removed from service in 2020 after the state of California lowered the Response Level advisories of PFOA and PFOS; two legacy PFAS compounds no longer produced in the United States.

Using an Ion Exchange (IX) treatment system made of highly porous resin that acts like powerful magnets that adsorb and hold onto contaminants, the facility can treat up to 4.6 million gallons of water per day. During treatment, contaminants such as PFAS are removed from the water before it goes into the distribution system.

“We are very proud to have acted quickly, to ensure that our customers are getting safe, reliable water continuing to meet all state and federal drinking water standards” said Serrano Water District’s President Greg Mills. “Also, having this facility online means that we can again utilize our groundwater to realize less expensive and more reliable than imported water.”

OCWD and 10 Orange County public water agencies filed a lawsuit against the manufacturers of PFAS, seeking to protect ratepayers and ensure that the associated costs, including but not limited to treatment and replacement water, are borne by the companies that developed and manufactured PFAS.

For additional information on OCWD’s comprehensive and robust PFAS response, please visit

The Orange County Water District is committed to enhancing Orange County’s groundwater quality and reliability in an environmentally friendly and economical manner. The following cities rely on the groundwater basin, managed by OCWD, to provide 77 percent of their water demands: Anaheim, Buena Park, Costa Mesa, Cypress, Fountain Valley, Fullerton, Garden Grove, Huntington Beach, Irvine, La Palma, Los Alamitos, Newport Beach, Orange, Placentia, Santa Ana, Seal Beach, Stanton, Tustin, Villa Park, Westminster, and Yorba Linda. For more information about OCWD, please visit, like @OCWaterDistrict on Facebook, follow @OCWDWaterNews on Twitter, follow @OCWD on Instagram, and follow Orange County Water District on LinkedIn.

Serrano Water District (SWD) was established in 1876 and provides potable water to the City of Villa Park and a small portion of the City of Orange. SWD receives its water supply from local surface water which is stored in Irvine Lake and groundwater from two wells located within the City of Villa Park. SWD provides up to approximately 2,900 acre feet of water annually to its residential customers. For more information, visit

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