US PFAS Contamination Map
Built from EPA UCMR5 data (2023–2025) — the first comprehensive national survey of PFAS levels in US tap water. Check your state, then enter your ZIP for utility-level results.
Reviewed for accuracy against EPA UCMR5 data and peer-reviewed literature · Updated May 2026
The short answer
PFAS contamination has been detected in public water systems across nearly every US state under EPA's UCMR5 programme. 29 PFAS compounds were monitored in thousands of utilities from 2023–2025. There is no safe level for PFOA or PFOS — the 4 ppt EPA limit is a legal threshold, not a health guarantee. Check your utility below.
PFAS contamination map — US by state
State-level detection patterns based on EPA UCMR5 national monitoring data (2023–2025). Hover any state to see aggregate detection status. Enter your ZIP below to check your specific utility's measured PFAS levels.
Data: EPA UCMR5 · 1.8M samples · 10,275 utilities · Last EPA release: January 2026 · Click any state to look up your utility
PFAS in your water by ZIP code
The map shows state-level patterns. Your utility's result is what matters.
Two utilities in the same county can have dramatically different PFAS levels depending on their water source. Enter your ZIP to see the UCMR5 results for your specific water system — not a county or state average.
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What the UCMR5 PFAS data shows
EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR5) is the most comprehensive PFAS survey ever conducted in US drinking water. Required testing covered thousands of public water utilities and 29 PFAS compounds between January 2023 and December 2025. The results are stark:
~45%
of tested utilities detected at least one PFAS
29
PFAS compounds monitored for the first time nationally
111M
Americans served by systems that detected PFHxA
The most widely detected PFAS by population were short-chain carboxylic acids — PFHxA, PFPeA, and PFBA — which were used as replacements for longer-chain compounds after PFOA and PFOS were phased out. These short-chain PFAS are highly mobile in water and harder to filter than their predecessors.
The regulated compounds — PFOA and PFOS — were detected at lower frequency nationally but at high concentrations near fluoropolymer manufacturing sites and military bases with AFFF firefighting foam history.
Why PFAS contamination is so widespread
PFAS contamination in US water systems reflects 70 years of widespread industrial and consumer use. The contamination pathways are multiple and overlapping:
- AFFF firefighting foam: Used at military bases, airports, and fire training facilities since the 1960s. Decades of use have created extensive groundwater plumes near hundreds of sites across every region of the US.
- Fluoropolymer manufacturing: Production of Teflon, Gore-Tex, and similar products released PFOA and PFOS into rivers and groundwater near plant sites — most notably Parkersburg, WV and Fayetteville, NC.
- Biosolids application: PFAS-containing sewage sludge ("biosolids") spread on agricultural land has contaminated groundwater and surface water in farming states across the Midwest and South.
- Consumer product runoff: Stain-resistant carpets, water-resistant clothing, food packaging, and non-stick cookware all contain PFAS that eventually reach wastewater treatment plants — which cannot remove them — and re-enter water supplies.
PFAS health risks: the MCL vs EWG gap
EPA's 2024 MCL of 4 ppt for PFOA and PFOS is the first binding federal limit. But the gap between the legal limit and what the science suggests is protective is striking:
| Compound | EPA MCL (2024) | EWG guideline | Gap |
|---|---|---|---|
| PFOA | 4 ppt | 0.004 ppt | 1,000× |
| PFOS | 4 ppt | 0.004 ppt | 1,000× |
| PFNA | 10 ppt | 0.3 ppt | 33× |
| PFHxS | 10 ppt | 1 ppt | 10× |
| HFPO-DA (GenX) | 10 ppt | 1 ppt | 10× |
PFOA and PFOS are classified by IARC as Group 2A probable human carcinogens. For carcinogens with no established safe dose, EWG derives its guidelines using cancer risk models rather than a threshold approach. The 1,000× gap means water can be legally compliant while still containing PFAS levels that concern independent scientists and toxicologists.
The groups most concerned by even low PFAS levels: pregnant women and those trying to conceive, infants (formula-fed from tap water), people who are immunocompromised, and anyone focused on long-term health and cancer prevention.
How to filter PFAS from tap water
Not all filters address PFAS. The key is NSF certification for the right standard:
| Filter type | PFAS removal | Certification |
|---|---|---|
| Reverse osmosis | 90–99% | NSF/ANSI 58 |
| Activated carbon block | Most long-chain PFAS | NSF/ANSI 53 |
| Whole-home carbon filter | Partial — varies | NSF/ANSI 53 (check label) |
| Standard pitcher (Brita etc.) | Not certified | NSF 42 only |
| Water ionizer / alkaliser | None | — |
Note on water ionizers (Kangen or similar): The built-in carbon pre-filter reduces chlorine — which helps limit disinfection byproduct formation — but does not remove PFAS, which are dissolved fluorinated compounds not addressed by carbon pre-filtration alone. For PFAS, a dedicated NSF 58 certified reverse osmosis system is necessary alongside any ionizer.
For detailed guidance on choosing a PFAS water filter, see our guide: PFAS water filter: what actually removes forever chemicals.
Frequently asked questions
Is there a PFAS contamination map of the US?
Yes. This page shows a PFAS contamination map built from EPA's UCMR5 national monitoring data (2023–2025), the most comprehensive PFAS survey of US public water systems ever conducted. The map shows detection status for utilities in our database by state. EPA also maintains a full national PFAS occurrence dataset at epa.gov/dwucmr.
Which states have the most PFAS in drinking water?
UCMR5 data shows the highest rates of PFAS detection in the Midwest, Northeast, and Southeast — particularly in states with legacy fluoropolymer manufacturing (North Carolina, Ohio, West Virginia) and states with high concentrations of military bases using AFFF firefighting foam. However, PFAS have been detected in water systems in nearly every state due to the widespread historic use of PFAS-containing products.
How do I find PFAS levels in my water by ZIP code?
Enter your ZIP code in the tool on this page or at the top of any WaterHealthCheck report page. We pull the UCMR5 results for your specific water utility — not just your state or county — so you see the actual measured PFAS levels for the water coming out of your tap.
What are safe PFAS levels in drinking water?
EPA's 2024 Maximum Contaminant Level is 4 ppt (parts per trillion) each for PFOA and PFOS, and 10 ppt each for PFHxS and HFPO-DA (GenX). The Environmental Working Group's health guideline is 0.004 ppt for PFOA and PFOS — 1,000 times stricter — because they apply a no-safe-threshold approach to probable carcinogens. Many scientists consider even 4 ppt too lenient for sensitive populations.
What are the most common PFAS detected in US tap water?
UCMR5 data shows the most widely detected PFAS in US drinking water are PFHxA (detected in systems serving 111 million people), PFPeA (101 million), PFBA (95 million), PFOA (extensively detected near manufacturing sites), and PFHxS (71 million people across 46 states). PFOS is less widespread nationally but highly concentrated near military installations.
How do I filter PFAS from tap water?
Reverse osmosis (RO) with NSF/ANSI 58 certification removes 90–99% of PFAS including PFOA, PFOS, and short-chain replacements. NSF 53 certified activated carbon block filters remove most long-chain PFAS but are less effective for short-chain compounds. Standard pitcher filters (Brita, etc.) are not certified for PFAS removal. Look for third-party NSF certification — not manufacturer claims.
What is UCMR5 and why does it matter for PFAS mapping?
UCMR5 is EPA's Fifth Unregulated Contaminant Monitoring Rule, which required thousands of US public water utilities to test for 29 PFAS compounds and lithium between 2023 and 2025. It is the first comprehensive national survey of PFAS in US drinking water and the dataset underlying this PFAS contamination map. The results directly informed EPA's 2024 PFAS drinking water regulations.
Does my water utility have PFAS?
The only way to know for sure is to check your specific utility's UCMR5 results. PFAS have been detected in systems serving tens of millions of Americans, but detection rates vary enormously by utility and geography. Enter your ZIP code in the tool below — we show the measured PFAS levels for your water system, not just regional averages.
Sources and methodology
- US EPA (2023–2025). Fifth Unregulated Contaminant Monitoring Rule (UCMR5) Occurrence Data. epa.gov/dwucmr
- US EPA (2024). PFAS National Primary Drinking Water Regulation (NPDWR). epa.gov/sdwa/pfas
- IARC (2023). PFOA and PFOS classified as Group 2A probable human carcinogens. IARC Monographs Vol. 135. iarc.who.int
- Environmental Working Group (2023). PFAS contamination in the US — 2023 update. ewg.org/tapwater
- Hu, X.C., Andrews, D.Q., Lindstrom, A.B., et al. (2016). Detection of poly- and perfluoroalkyl substances (PFASs) in US drinking water linked to industrial sites. Environmental Science & Technology Letters, 3(10), 344–350.
- Schaider, L.A., Balan, S.A., Blum, A., et al. (2017). Fluorinated compounds in US fast food packaging. Environmental Science & Technology Letters, 4(3), 105–111.
- WaterHealthCheck UCMR5 data pipeline: map data sourced from EPA UCMR5 occurrence file, aggregated per public water system and state. See our methodology.