93% of US water systems with PFAS detections have no treatment to remove the chemicals, and small systems serving under 500 people face per-household costs up to $3,570 to install one

The EPA finalized the first national drinking water standards for PFAS in April 2024, setting maximum contaminant levels as low as 4 parts per trillion for PFOA and PFOS — two of the most common 'forever chemicals.' But only 8% of US water systems are equipped with filters capable of removing PFAS, meaning 92% of systems where PFAS has been detected are delivering contaminated water with no treatment in place. The problem is worst for the roughly 45,000 small water systems serving fewer than 500 people each: installing granular activated carbon or reverse osmosis systems costs these tiny utilities between $305 and $3,570 per household annually, because so few ratepayers share the capital and operating expense. The health stakes are not theoretical. PFAS compounds bioaccumulate in the human body with half-lives of 4–8 years. Exposure at levels now considered unsafe by the EPA is linked to kidney cancer, testicular cancer, thyroid disease, liver damage, immune suppression, and developmental effects in children. Communities near military bases are especially hard-hit: in Security, Colorado, one well tested at 1,370 parts per trillion of PFOS — nearly 343 times the new EPA limit. The Air Force spent $41 million building treatment plants for three small communities near Peterson Space Force Base, but that was an exceptional case where the Department of Defense accepted responsibility. Most small towns near industrial PFAS sources have no such benefactor. The structural reason this persists is economic: PFAS treatment technology exists but is expensive and energy-intensive. Granular activated carbon filters require regular replacement, and the spent carbon itself becomes PFAS-contaminated waste with no clear disposal pathway. The EPA delayed compliance deadlines to 2031 and in May 2025 proposed repealing standards for four of the six regulated PFAS compounds, weakening the regulatory pressure on utilities to act. Only 7% of very small water systems use any advanced filtration at all. The result is a two-tier water system: wealthy suburban utilities with the rate base to afford treatment, and rural communities where people drink PFAS-contaminated water because their utility literally cannot afford the equipment to remove it.