Contaminant · PFAS
6:2 FTS in drinking water
1H,1H,2H,2H-perfluorooctane sulfonic acid, a fluorotelomer used in newer firefighting foams.
What the rules say
6:2 FTS has no federal limit; EPA published a toxicity assessment in 2024 but no drinking water reference concentration.
What EPA's assessment says
EPA's 2024 human health toxicity assessment for 6:2 FTS cites kidney and developmental effects in animal studies.
Read the EPA source for 6:2 FTS.
Across the country
EPA tested 10,307 water systems for 6:2 FTS and found it in 183. Half of the systems that found it measured less than 9.9 ppt, and one in ten measured more than 62.5 ppt.
EPA's final UCMR 5 occurrence file contains 66,348 6:2 FTS results from 10,307 systems. 253 results were at or above the minimum reporting level, across 183 systems. Among detections, the median was 9.9 ppt and the 90th percentile was 62.5 ppt.
Systems with the highest recorded 6:2 FTS results
| System | State | Population served | Recorded value | Records / periods |
|---|---|---|---|---|
| Telford Borough Authority PA1460050 | Pennsylvania | 7,700 | 226 ppt | 6 |
| City of Sugar Land TX0790005 | Texas | 90,909 | 672 ppt | 2 |
| Mdwasa - Main System FL4130871 | Florida | 2,377,460 | 190 ppt | 3 |
| City of Gonzales TX0890001 | Texas | 9,172 | 597 ppt | 1 |
| Emerald Coast Utilities Authority (Ecua) FL1170525 | Florida | 242,172 | 220 ppt | 4 |
| Cross Timbers WSC TX0610020 | Texas | 8,751 | 441 ppt | 1 |
| Gwa Northern Water System GU0000006 | Guam | 139,207 | 148 ppt | 5 |
| North Bay Village, City of FL4130970 | Florida | 8,317 | 136 ppt | 2 |
| Georgetown Water Department DE0000592 | Delaware | 7,259 | 180 ppt | 1 |
| Hialeah, City of FL4130604 | Florida | 238,000 | 91.1 ppt | 2 |
| Mccoy WSC TX0070023 | Texas | 9,621 | 119 ppt | 1 |
| Fallbrook Utility District TX1010340 | Texas | 6,720 | 104 ppt | 1 |
| Emmaus Borough Public Water PA3390032 | Pennsylvania | 14,000 | 64.5 ppt | 2 |
| Two Way SUD TX0910022 | Texas | 6,804 | 97.1 ppt | 1 |
| Bal Harbour Village FL4130077 | Florida | 3,209 | 84.0 ppt | 2 |
| Miami Beach, City of FL4130901 | Florida | 100,000 | 89.0 ppt | 1 |
| Bremen GA1430000 | Georgia | 6,200 | 168 ppt | 1 |
| Mountain Regional Water Ssd UTAH22137 | Utah | 8,245 | 55.0 ppt | 2 |
| Pembroke Pines, City of FL4061083 | Florida | 187,459 | 39.1 ppt | 2 |
| City of Pompano FL4061129 | Florida | 99,400 | 62.0 ppt | 1 |
| City of Morgans Point Resort TX0140116 | Texas | 5,000 | 115 ppt | 1 |
| Four Way SUD TX0030020 | Texas | 6,684 | 54.6 ppt | 1 |
| Hesperia WD CA3610024 | California | 100,744 | 50.3 ppt | 1 |
| City of Oxford MS0360011 | Mississippi | 28,500 | 22.9 ppt | 2 |
| Fort Drum NY2212214 | New York | 34,000 | 26.0 ppt | 2 |
Filters and testing
NSF/ANSI 58 (reverse osmosis)
A standard number by itself is not a contaminant claim. Check the product's current certification listing and performance data sheet for 6:2 FTS or the specific contaminant you want to reduce. A utility-level record is not a test of your own faucet.