PFAS in drinking water
PFAS — the “forever chemicals” — are a real and reasonable concern. They are also one of the clearest cases where the certified, effective fix is smaller and cheaper than people expect, because PFAS harm you through what you drink.
What it is
PFAS (per- and polyfluoroalkyl substances) are a large family of synthetic chemicals used since the mid-20th century in non-stick, stain-resistant, and firefighting products. They are nicknamed “forever chemicals” because they break down extremely slowly and can persist in water and the body. The two most studied are PFOA and PFOS. They are colorless and tasteless in water, so testing is the only way to detect them.
Health effects, stated plainly
Research links higher long-term PFAS exposure to effects including changes in cholesterol, reduced immune response, effects on the liver and on development, and increased risk of certain cancers. As with most drinking-water contaminants, the concern is sustained exposure over time, not a single glass. This is why agencies have moved to limit PFAS where it occurs. For a primary-source overview, see the CDC's ATSDR. CDC/ATSDR on PFAS →
Where it comes from
PFAS reach water from industrial discharges, firefighting foam used at airports and military sites, landfills, and the breakdown of consumer products. Because they travel and persist, they show up in both public supplies and private wells — often far from the original source. Wells near known industrial or firefighting-foam sites warrant particular attention.
How to know if you have it
PFAS cannot be tasted, seen, or smelled, and they require a specialized laboratory test (a standard mineral panel will not detect them). If you are on a private well — especially near a potential source — a certified PFAS lab test is the way to know. Public systems are increasingly required to monitor and report PFAS, so your utility may have data too.
What the current limit is
As of June 2026, the EPA enforceable limits (MCLs) are 4.0 parts per trillion (ppt) for PFOA and 4.0 ppt for PFOS, from the 2024 PFAS National Primary Drinking Water Regulation, with a health goal (MCLG) of zero for each. This area is genuinely in flux: EPA has announced it will keep the PFOA and PFOS limits but has proposed extending the compliance deadline for public systems to 2031, and has separately proposed rescinding the limits for four other PFAS (PFHxS, PFNA, GenX/HFPO-DA, and the hazard-index mixture). So the PFOA/PFOS numbers are current, but timelines and the other PFAS limits may change. EPA PFAS drinking-water page (verified June 2026) →
What reduces it
The well-established treatment types for PFAS are reverse osmosis, certain activated-carbon filters, and ion-exchange resin. Reverse osmosis is among the most robust because it also captures the harder-to-remove short-chain PFAS that carbon alone can struggle with. Because PFAS is ingestion-route, a certified point-of-use unit at the kitchen tap is the practical, effective choice; whole-home RO is impractical for most households.
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Get my recommendationEducational information, not medical or regulatory advice. Regulatory limits are health references, not mandates to treat. For your specific water, consult a certified laboratory and your local utility, and confirm any product's current certification for your exact model in the NSF, IAPMO, or WQA database. Regulatory figures verified against the U.S. EPA in June 2026 and may change — PFAS rules are especially active.