Water systems with PFOA or PFOS at or above 4 ppt

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Highest PFOA or PFOS result ≥ 4.0 ppt in EPA testing 2023–2025 · circle size = people served

PFAS in drinking water

Between 2023 and 2025 EPA had 9,947 community water systems test for 29 PFAS (UCMR 5). 1,693 measured PFOA or PFOS at or above 4.0 ppt; 3,457 detected at least one PFAS.

The limits

In April 2024 EPA set legally enforceable maximum contaminant levels of 4.0 parts per trillion for PFOA and for PFOS, with a compliance deadline at the end of the decade. Results here are the highest single measurement in the testing period, which is how a first screening is usually read.

What you can do

Check your system’s results on its page here and in its Consumer Confidence Report. Point-of-use filters certified to NSF/ANSI 53 or 58 for PFOA/PFOS reduce PFAS at the tap.

What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.