New federal standards for "forever chemicals" affect California wells

At least 796 wells in 214 water systems in California would exceed new federal standards for per- and polyfluoroalkyl chemicals, known as "forever chemicals," according to 2023 data from the California State Water Resources Control Board. This amounts to 53% of tested water systems and 42% of tested wells. Under a more lax California guideline, just 224 wells in 85 water systems had excessive amounts of the chemicals.

Newly announced federal standards that determine whether water is contaminated with unsafe levels of forever chemicals would find at least 796 measured wells in violation within 214 water systems across California. This would encompass 53% of measured water systems and 42% of measured wells, according to 2023 data from the California State Water Resources Control Board. Using California standards, just 224 wells in 85 water systems would be in violation.
This analysis calculated average levels in wells that were measured multiple times in 2023. Wells that violated one of three conditions were flagged as in violation: PFOS or PFOA levels over 4 ng/L, HFPO-DA, PFHxS, or PFNA over 10 ng/L, or a calculated hazard index based on the presence of four other forever chemicals higher than 1.
Chart: John Osborn D'Agostino, CalMattersSource: California State Water Resources Control BoardGet the dataCreated with Datawrapper