PFAS — The 'Forever Chemicals' in Your Tap Water

In the early 2000s, a lawyer named Rob Bilott began investigating why cattle near a DuPont factory in Parkersburg, West Virginia were dying at alarming rates. The culprit turned out to be PFOA — a chemical used to make Teflon — that had been discharged into the local water supply for decades.

What Bilott uncovered was that DuPont had known about PFOA's toxicity for decades and continued to contaminate Parkersburg's water supply anyway. The C8 Health Project that followed — one of the largest environmental health studies ever conducted — examined over 69,000 people exposed to PFOA through the drinking water and found probable links to six diseases.[3]

In April 2024 — more than 70 years after PFOA was first introduced into commerce — the EPA finally set the first-ever enforceable limits for PFAS in drinking water: 4 parts per trillion for PFOA and PFOS.[2] The level at which health effects had been documented was so low that regulators had spent decades arguing it was too impractical to regulate.

PFAS — per- and polyfluoroalkyl substances — is an umbrella term for over 12,000 synthetic compounds built around the carbon-fluorine bond, one of the strongest in chemistry. That bond is why they work so well: they repel water, oil, and heat. It's also why they persist. "Forever chemicals" is not marketing language — PFAS do not break down in the environment or in the human body under normal conditions. They accumulate in soil, groundwater, and wildlife food chains. They accumulate in human blood, liver, and kidneys. Once they're in, they're in for years.[3]

The immune effects are particularly alarming: a 2012 JAMA study found that children with higher PFAS exposure had significantly reduced antibody responses to routine vaccinations.[1] The effect was dose-dependent — the more PFAS, the weaker the immune response. Kidney and testicular cancer, thyroid disease, reproductive harm, and liver disease have all been linked to PFAS exposure in the C8 and subsequent studies.

For people in heavily contaminated areas, drinking water is the dominant exposure source by far. For everyone else, dietary sources — especially food packaging, microwave popcorn bags, and fast-food wrappers — and consumer products contribute to a meaningful background burden.

PFAS contamination in US drinking water is widespread — but not evenly distributed. Knowing where concentration is highest matters for understanding personal risk.

The highest-concentration contamination in the US clusters around military bases and airports where AFFF (aqueous film-forming foam) — a PFAS-containing firefighting foam — was used for training and accident response for decades.[2] Over 700 military installations have documented PFAS groundwater contamination, many at levels far above the new EPA MCLs.

Manufacturing facilities that produce or use PFAS compounds have created local contamination plumes in surrounding groundwater. DuPont's Washington Works plant in Parkersburg remains the most documented, but similar patterns exist around facilities in North Carolina, Minnesota, and elsewhere.[3]

Analysis by the Environmental Working Group and others suggests PFAS are detectable in drinking water serving over 200 million Americans. Private wells are not subject to Safe Drinking Water Act regulations and are not systematically tested — residents near PFAS sources may have no idea they're exposed.[2]

The good news on PFAS is that filtration works — unlike lead, which requires plumbing replacement, PFAS can be removed at the tap with the right technology.

Reverse osmosis systems certified to NSF/ANSI Standard 58 remove 90%+ of PFAS from water and are the gold standard for home use.[2] They also remove lead, arsenic, nitrates, and disinfection byproducts — a strong all-round choice for families. High-quality activated carbon block filters — not granular activated carbon, which is significantly less effective — also reduce PFAS, though not as completely as RO.

Standard pitcher filters are not certified for PFAS removal. Check NSF certification before assuming a filter is protective — "reduces contaminants" on the label is not the same as an NSF 58 PFAS-specific certification.

For people near military bases or industrial facilities, filtration is not a precautionary exercise — it's a direct health priority. Retest your tap water annually if contamination is known in your area, as concentration levels can change as utilities upgrade treatment or as contamination plumes shift.