Published April 5, 2026 · Updated monthly
PFAS in Drinking Water: Which Systems Are Affected
PFAS (per- and polyfluoroalkyl substances) are synthetic "forever chemicals" found in thousands of US water systems. In April 2024, the EPA set the first-ever enforceable limits for PFAS in drinking water: 4 parts per trillion (ppt) for PFOA and PFOS. Studies link PFAS exposure to cancer, thyroid disease, immune system effects, and reproductive problems. Here is what the data shows about PFAS in your water.
What Are PFAS?
PFAS are a group of over 12,000 synthetic chemicals used since the 1950s in non-stick cookware (Teflon), water-resistant clothing (Gore-Tex), firefighting foam (AFFF), and food packaging. They are called "forever chemicals" because they do not break down in the environment or the human body. Nearly all Americans have detectable PFAS levels in their blood.
The New EPA Limits
The EPA's 2024 PFAS rule set these maximum contaminant levels (MCLs):
| PFAS Compound | EPA Limit (MCL) | Health Concern |
|---|---|---|
| PFOA | 4 ppt | Cancer, liver damage, immune effects |
| PFOS | 4 ppt | Cancer, thyroid disease, reproductive effects |
| PFNA | 10 ppt | Developmental effects, liver damage |
| PFHxS | 10 ppt | Thyroid disease, immune effects |
| GenX (HFPO-DA) | 10 ppt | Cancer, developmental effects |
How PFAS Gets in Water
- Military bases and airports — AFFF firefighting foam used in training exercises has contaminated groundwater near hundreds of military sites
- Industrial facilities — PFAS manufacturing plants and facilities that use PFAS in production discharge into waterways
- Landfills — PFAS-containing consumer products leach into groundwater from landfill runoff
- Wastewater treatment plants — Conventional treatment does not remove PFAS, so treated wastewater can spread contamination
How to Remove PFAS From Your Water
Standard water filters (basic carbon pitchers like Brita) do NOT effectively remove PFAS. You need:
- Reverse osmosis (RO) systems — Remove 90-99% of PFAS. Point-of-use RO systems cost $200-500 and install under the kitchen sink.
- Activated carbon block filters — NSF-certified carbon block filters (not granular activated carbon) can remove 70-95% of PFAS. Look for NSF P473 certification specifically.
- Ion exchange filters — Effective for PFAS but more expensive and typically used in whole-house systems.
See our detailed PFAS contaminant page for more information on health effects and filter recommendations.
Check your water system's PFAS status by looking up your address on Is Water Safe.
Frequently Asked Questions
Possibly. PFAS has been detected in water systems serving over 100 million Americans. The only way to know for sure is to check your water system's testing results. Search your water system on Is Water Safe or request your utility's Consumer Confidence Report.
Standard Brita pitchers with granular activated carbon filters are NOT effective at removing PFAS. You need a reverse osmosis system or an NSF P473-certified carbon block filter for meaningful PFAS reduction.
No. Boiling water does NOT remove PFAS. In fact, boiling can concentrate PFAS by evaporating water while the chemicals remain. You need physical filtration (reverse osmosis or carbon block) to remove PFAS.
Research links PFAS exposure to increased cancer risk (kidney and testicular cancer), thyroid disease, immune system suppression, reproductive problems, and developmental effects in children. The EPA considers PFAS at any level above its new MCLs to pose a health risk.