Posted May 30, 2025
Cal Water has completed construction and installation of treatment vessels on two local groundwater wells, and all active wells in Cal Water’s Visalia District are now in compliance with new—but not yet in effect—water quality standards for certain per- and polyfluoroalkyl substances (PFAS). The work was done well in advance of the current 2029 deadline that utilities were given by the U.S. Environmental Protection Agency (EPA) in April 2024 to comply with the new National Primary Drinking Water Regulation for certain PFAS.
Crews began installing ion-exchange treatment and associated site piping in December 2024 at a well site on West Packwood Drive, and granular-activated carbon treatment and associated site piping at a well site on Akers Street. The different treatment methods were determined based on well production capacity and facility size. Cal Water recently received approval from the State Water Resources Control Board’s Division of Drinking Water to return to operation these key water sources in time for the heavier-water usage summer months. The district began operating one of the wells this week and will begin operating the second well next week.
“We’ve worked hard to bring impacted sources in Visalia into compliance with the new maximum contaminant levels (MCLs) sooner than required,” said Stephen Johnson, District Manager of Cal Water’s Visalia District. “These improvements enhance water quality, along with supply and system reliability, for both our community’s daily and emergency needs.”
PFAS are manmade compounds that are found in a number of everyday products; these compounds are soluble in water and can travel long distances. Under the current PFAS regulation, EPA established MCLs of 4 parts per trillion (ppt) for both PFOA and PFOS; MCLs of 10 ppt for PFHxS, PFNA, and GenX; and a combined Hazard Index of 1.0 for PFBS, PFHxS, PFNA, and GenX. Under the new PFAS regulation, water utilities across the country are required to monitor for these PFAS by 2027, and impacted water systems must comply with the MCLs and Hazard Index by 2029.
Cal Water regularly assesses the water quality of its existing supply sources and began monitoring all of its active water sources for these PFAS prior to the EPA mandate, Johnson said. As a result, Cal Water was well-positioned to treat critical water sources in Visalia within the compliance timeframe, he added.
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