Contaminant · PFAS
PFOA in drinking water
Perfluorooctanoic acid, a legacy PFAS used in nonstick coatings and firefighting foam. One of the two PFAS with an enforceable federal drinking water limit.
highest complete sampling-location average; sampled 2023–2025. Source: EPA records; Potrero Elementary School (CA3700963).
What the rules say
EPA set an enforceable Maximum Contaminant Level of 4.0 ng/L (ppt) for PFOA in April 2024, with compliance required from 2029; in May 2026 EPA proposed keeping this limit and letting systems request until 2031 to comply. Compliance is judged on running annual averages at each sampling point, so a single UCMR 5 result above 4.0 ng/L is not a violation.
What EPA's assessment says
EPA set the health goal (MCLG) for PFOA at zero. EPA's 2024 rule cites its health effects assessment linking PFOA exposure to certain cancers, immune and developmental effects, and changes in cholesterol.
Across the country
EPA tested 10,307 water systems for PFOA and found it in 1,305. Half of the systems that found it measured less than 6.1 ppt, and one in ten measured more than 12.7 ppt.
EPA's final UCMR 5 occurrence file contains 66,359 PFOA results from 10,307 systems. 4,354 results were at or above the minimum reporting level, across 1,305 systems. Among detections, the median was 6.1 ppt and the 90th percentile was 12.7 ppt.
784 systems had a result at or above the reference on the page's stated comparison basis. For contaminants with a limit, that basis is the yearly average at the highest sampling location, not the highest single sample.
Systems with the highest recorded PFOA results
| System | State | Population served | Recorded value | Records / periods |
|---|---|---|---|---|
| Potrero Elementary School CA3700963 | California | 300 | 181 ppt | 2 |
| Lubeck PSD WV3305404 | West Virginia | 11,724 | 89.8 ppt | 1 |
| Pequenakonck Elementary School NY5907717 | New York | 700 | 55.8 ppt | 1 |
| Caernarvon TWP Auth PA3060052 | Pennsylvania | 4,245 | 51.8 ppt | 2 |
| Raynham Center Water District MA4245000 | Massachusetts | 10,964 | 48.7 ppt | 3 |
| Verona Water Department NJ0720001 | New Jersey | 13,641 | 43.4 ppt | 5 |
| Palmerton Municipal Authority PA3130012 | Pennsylvania | 7,000 | 39.8 ppt | 2 |
| Payson Town of AZ0404032 | Arizona | 17,682 | 39.7 ppt | 23 |
| Tempe City of AZ0407100 | Arizona | 165,000 | 37.9 ppt | 8 |
| Livingston TWP Div of Water NJ0710001 | New Jersey | 27,391 | 36.9 ppt | 21 |
| Savannah Valley U.D. TN0000613 | Tennessee | 30,571 | 32.0 ppt | 2 |
| Grand Bay Water Works Board AL0000983 | Alabama | 11,100 | 30.7 ppt | 2 |
| Ridgewood Water NJ0251001 | New Jersey | 61,700 | 30.6 ppt | 33 |
| Parkersburg Utility Board WV3305407 | West Virginia | 34,251 | 29.1 ppt | 2 |
| Pa American Audubon PA1460055 | Pennsylvania | 8,200 | 29.0 ppt | 14 |
| Ho Ho Kus Water Dept NJ0228001 | New Jersey | 4,060 | 29.0 ppt | 8 |
| Gonzalez Utilities Association, INC. FL1170302 | Florida | 6,668 | 28.1 ppt | 6 |
| Brookwood Comm Wtr System NC0326127 | North Carolina | 15,380 | 26.7 ppt | 29 |
| Augusta-Richmond Co Ws GA2450000 | Georgia | 204,000 | 26.6 ppt | 2 |
| Orangewood Water System FL6511311 | Florida | 6,464 | 26.5 ppt | 10 |
| Williamstown Water Dept WV3305412 | West Virginia | 3,469 | 26.1 ppt | 2 |
| Robeson County Water System NC0378055 | North Carolina | 67,970 | 26.0 ppt | 6 |
| Yeshiva Farm Settlement NY5903150 | New York | 300 | 25.0 ppt | 4 |
| Gadsden, the Wwsb of the City of AL0000577 | Alabama | 44,637 | 23.5 ppt | 4 |
| Bealeton Regional VA6061129 | Virginia | 4,250 | 23.1 ppt | 8 |
Filters and testing
NSF/ANSI 53 or NSF/ANSI 58 with a PFOA/PFOS reduction claim
A standard number by itself is not a contaminant claim. Check the product's current certification listing and performance data sheet for PFOA or the specific contaminant you want to reduce. A utility-level record is not a test of your own faucet.