PFAS Contamination Map: Is Your City Affected? (2026 Update)

EPA data shows PFAS in 45% of US tap water. Check every known contamination site.

How Widespread

PFAS contamination is far more widespread than most people realize. A 2023 USGS study found PFAS in approximately 45% of US tap water samples tested, including both urban and rural areas. EWG's contamination tracker has identified over 9,552 known PFAS contamination sites across all 50 states.

The EPA's UCMR5 monitoring program, which required large water systems to begin testing in 2023, is producing the most comprehensive picture yet. Early results show that hundreds of water systems serving millions of people have detectable PFAS. Among the 1,000 cities we track on CheckMyTap, 965 have PFAS testing data available, and a significant percentage show detections above zero.

The most heavily contaminated areas cluster around known PFAS sources: military bases that used AFFF firefighting foam, industrial manufacturing sites (especially fluorochemical, textile, and paper plants), airports, and wastewater treatment plants. But PFAS also shows up in areas with no obvious point source, because these chemicals travel through groundwater and can spread for miles from their origin.

States with the highest number of contaminated sites include California, Michigan, New Jersey, Florida, and North Carolina. But PFAS has been detected in every state that has conducted testing, including rural areas far from industrial activity.

Where It Comes From

PFAS enters drinking water from several distinct sources, each creating a different contamination pattern on the map:

• Military bases and airports: Aqueous film-forming foam (AFFF), used to fight fuel fires since the 1960s, is the single largest known source. The DoD has identified over 700 military installations with confirmed or suspected PFAS contamination. Contamination plumes often extend miles beyond base boundaries into surrounding communities.
• Industrial manufacturing: Facilities that manufactured or used PFAS in products (3M, DuPont/Chemours, and hundreds of others) discharged PFAS through wastewater and air emissions. The Fayetteville Works plant in North Carolina contaminated the Cape Fear River, affecting the drinking water of 350,000+ people.
• Wastewater treatment plants: These facilities concentrate PFAS from household and industrial sources, then discharge it into rivers used as drinking water sources downstream.
• Landfills: Consumer products containing PFAS (nonstick cookware, food wrappers, stain-resistant fabric) break down in landfills and release PFAS into groundwater through leachate.
• Biosolids/fertilizer: Sewage sludge applied as agricultural fertilizer contains PFAS that then leaches into soil and groundwater, contaminating nearby wells.

Your Levels

To find out if your water is affected, start with CheckMyTap's city search. We compile UCMR5 data and other federal monitoring results for 1,000 US cities, showing your total PFAS level, specific PFOA and PFOS concentrations, and how they compare to the EPA's 4 ppt limit.

When reading PFAS data, understand what the numbers mean. The EPA's MCL of 4 ppt for PFOA and PFOS is measured individually, not combined. So water with 3 ppt PFOA and 3 ppt PFOS is technically compliant for each compound, but your total PFAS exposure is 6 ppt. The hazard index approach in the new rule partially addresses this for five regulated PFAS, but there are over 15,000 PFAS compounds and only six are regulated.

"Non-detect" on a water report does not mean zero PFAS. It means levels were below the lab's detection limit, which varies from 2-10 ppt depending on the testing method. Additionally, UCMR5 monitoring only covers large water systems. If your city is not in our database, contact your utility directly to ask about PFAS testing or request their most recent Consumer Confidence Report (CCR).

Filtering PFAS

If your city shows PFAS above 4 ppt, install an NSF P473 certified filter on your drinking water tap. A Clearly Filtered pitcher or under-sink RO system both work — the key is verified PFAS certification, not marketing claims. If your city shows non-detect, you are likely fine but can still test independently for peace of mind.

For chlorine, taste, and basic contaminants: Any NSF 42/53 certified carbon filter works. This includes Brita, PUR, and most fridge filters. Cost: $28-100.

For PFAS, lead, and health-critical contaminants: Look for NSF P473 (PFAS) or NSF 53 (lead) certification. The Clearly Filtered pitcher covers both. For maximum protection, a reverse osmosis system removes 90-99% of virtually all contaminants.

For hard water: No filter removes hardness. You need a water softener (ion exchange). This is the #1 misconception in water treatment: softeners and filters solve completely different problems.