Forty-five percent of US tap water contains detectable PFAS. That’s the headline finding from the 2023 USGS study — the most comprehensive national survey of PFAS in drinking water conducted to date.
But the number obscures something important. Contamination isn’t random. It clusters around specific sources. And those sources are often not reflected in what your utility tells you.
The Main Sources of PFAS Contamination
Military bases and airports. Aqueous film-forming foam (AFFF) was the standard firefighting foam used by the US military from the 1960s through the 2010s. AFFF contains high concentrations of PFOS and PFOA. Decades of training exercises soaked foam into the soil at hundreds of installations. The AFFF then leached into groundwater serving nearby communities.
The Department of Defense identified more than 700 installations where PFAS may have contaminated groundwater. Some communities near these bases have recorded PFAS levels in the hundreds of parts per trillion — many times the EPA’s 4 ppt limit.
Industrial manufacturing sites. The manufacturing of PFAS and PFAS-containing products releases PFAS into air and water. DuPont’s Washington Works plant in Parkersburg, West Virginia contaminated the drinking water of more than 70,000 people with PFOA over decades, as documented in the C8 Health Project. 3M’s plants in Minnesota contaminated the Mississippi River.
Wastewater treatment plants. PFAS from household and industrial sources flow into municipal wastewater. Conventional treatment doesn’t remove them. The treated water is discharged into rivers and streams that supply downstream drinking water systems. The sludge (biosolids) spread as agricultural fertilizer also contains PFAS.
Landfills. Household products containing PFAS end up in landfills. Rainwater percolates through the waste and carries PFAS into leachate, which can contaminate adjacent groundwater if the landfill liner fails.
How to Find Your Local PFAS Data
Three sources, in order of reliability:
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Your state’s drinking water database. Most states now maintain searchable databases of utility test results. Search for your state name plus “drinking water data” or “water quality results.”
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EPA’s UCMR5 data. The EPA’s Fifth Unregulated Contaminant Monitoring Rule required large utilities to test for 29 PFAS compounds between 2021 and 2025. Results are published on EPA’s website. This is more detailed than most CCRs.
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The EWG PFAS contamination map. The Environmental Working Group aggregates publicly available contamination data. Useful for an overview, but may not reflect your specific utility’s most recent results.
None of these sources covers private wells. If you’re on a well, you need to test independently.
Testing Your Own Water
For the most accurate picture, use a certified mail-in lab that applies EPA Method 533 or Method 537.1. These methods detect a much wider range of PFAS compounds than older testing methods. Standard at-home test strips can’t detect PFAS — the concentrations are measured in parts per trillion, which is far below what colorimetric tests can show.
What to look for in a lab:
- State-certified (look for NELAP certification or your state’s equivalent)
- Uses EPA Method 533 or 537.1
- Reports results in parts per trillion
- Provides written chain-of-custody documentation
Turnaround time is typically 1 to 3 weeks. Cost ranges from about $150 to $400 depending on how many compounds you’re testing for. A comprehensive PFAS panel testing for 30+ compounds runs on the higher end.
The results will tell you which specific PFAS compounds are present and at what concentrations. That matters because different compounds have different health implications and different regulatory limits.
What Utilities Are Doing About It
The EPA’s April 2024 rule gave water systems until April 2027 to assess their systems and until 2029 to install treatment if needed. The EPA estimates that 6 to 10% of water systems will need to take action to meet the new limits.
In the meantime, your utility may or may not be actively treating for PFAS. Granular activated carbon (GAC) and high-pressure membrane systems (nanofiltration, reverse osmosis) can reduce PFAS in treatment, but they’re expensive. Many smaller systems are waiting for federal infrastructure funding before installing them.
For what to do at the tap: How to Remove PFAS from Drinking Water