Contaminant · PFAS
PFNA in drinking water
Perfluorononanoic acid, a long-chain PFAS used as a processing aid in fluoropolymer manufacturing.
highest complete sampling-location average; sampled 2023–2025. Source: EPA records; Emmaus Borough Public Water (PA3390032).
What the rules say
The April 2024 PFAS rule set a 10 ng/L (ppt) limit for PFNA. In May 2026 EPA proposed rescinding that limit. Until a final decision, the 10 ng/L figure is shown for reference only.
What EPA's assessment says
EPA's 2024 rule cites health effects assessments associating PFNA with developmental, liver and immune effects.
Across the country
EPA tested 10,307 water systems for PFNA and found it in 83. Half of the systems that found it measured less than 6.5 ppt, and one in ten measured more than 17.8 ppt.
EPA's final UCMR 5 occurrence file contains 66,359 PFNA results from 10,307 systems. 176 results were at or above the minimum reporting level, across 83 systems. Among detections, the median was 6.5 ppt and the 90th percentile was 17.8 ppt.
16 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 PFNA results
| System | State | Population served | Recorded value | Records / periods |
|---|---|---|---|---|
| Emmaus Borough Public Water PA3390032 | Pennsylvania | 14,000 | 85.4 ppt | 4 |
| Capitol Water Corp ID4010022 | Idaho | 9,000 | 37.5 ppt | 4 |
| East Greenwich TWP Water Dept NJ0803001 | New Jersey | 9,900 | 36.7 ppt | 1 |
| City of Pflugerville TX2270014 | Texas | 63,464 | 24.8 ppt | 4 |
| Locust Valley WD NY2902833 | New York | 7,500 | 22.1 ppt | 2 |
| Palmerton Municipal Authority PA3130012 | Pennsylvania | 7,000 | 18.5 ppt | 2 |
| Georgetown Water Department DE0000592 | Delaware | 7,259 | 17.5 ppt | 3 |
| Manville WSC TX2270033 | Texas | 39,648 | 16.5 ppt | 3 |
| Westville Water Department NJ0821001 | New Jersey | 6,000 | 16.2 ppt | 2 |
| Emerald Coast Utilities Authority (Ecua) FL1170525 | Florida | 242,172 | 14.8 ppt | 2 |
| West Deptford TWP Water Dept NJ0820001 | New Jersey | 22,000 | 13.5 ppt | 7 |
| Ho Ho Kus Water Dept NJ0228001 | New Jersey | 4,060 | 13.5 ppt | 5 |
| Pequenakonck Elementary School NY5907717 | New York | 700 | 13.2 ppt | 1 |
| Fallsburg Who-Ls-Sf NY5203324 | New York | 7,850 | 12.7 ppt | 2 |
| Quakertown Boro PA1090082 | Pennsylvania | 12,800 | 12.0 ppt | 2 |
| Ambler Boro Water Dept PA1460020 | Pennsylvania | 20,000 | 11.7 ppt | 3 |
| City of Gridley CA0410004 | California | 7,269 | 9.8 ppt | 2 |
| Manhasset Lakeville WD NY2902836 | New York | 43,000 | 9.5 ppt | 1 |
| Potrero Elementary School CA3700963 | California | 300 | 9.3 ppt | 2 |
| Aqua Pa Main System PA1460073 | Pennsylvania | 822,600 | 8.8 ppt | 7 |
| Veolia Water Delaware, INC DE0000564 | Delaware | 100,495 | 8.4 ppt | 8 |
| City of Fresno CA1010007 | California | 545,716 | 8.0 ppt | 6 |
| Williston Park (V) NY2902858 | New York | 7,287 | 7.8 ppt | 2 |
| Brooklawn Water Departme NJ0407001 | New Jersey | 2,300 | 7.6 ppt | 1 |
| Garden City Water and Sewer System ID4010066 | Idaho | 12,500 | 7.6 ppt | 2 |
Filters and testing
NSF/ANSI 53 or NSF/ANSI 58 with a PFAS reduction claim
A standard number by itself is not a contaminant claim. Check the product's current certification listing and performance data sheet for PFNA or the specific contaminant you want to reduce. A utility-level record is not a test of your own faucet.