Water System snapshot · PFOS, highest monitored result
U.S. Cities Where PFAS Exceeds the 2024 Federal Limit
25 ranked water systems by pfos, highest monitored result, from a fixed snapshot on 2026-09-16 (data cutoff EPA UCMR5 (2024), released Jan 2026). Shown in the snapshot's published order.
A ranking is not a safety verdict
This compares one published metric for one entity class. It does not summarize everything about a system, and it is not the water at a household tap.
Snapshot 2026-09-16 · cutoff EPA UCMR5 (2024), released Jan 2026 A snapshot is immutable: its ordering belongs to the stated date, data cutoff, methodology, and exclusions.
Methodology and limitations
How this snapshot is built
From EPA UCMR5 (2024) occurrence data, community water systems are ranked by their highest reported PFOS result against the 4.0 ng/L federal maximum. Only systems with a published PFAS finding and a city report are listed.
Reading the order
Figures are monitored public-system results for the stated period, not necessarily current treated water. Utilities may treat before delivery. A result above a limit is a regulatory exceedance, not an individual health verdict.
Exclusions
640 excluded. Shown: the highest monitored PFOS results among cities with a PFAS page. Additional cities also exceed the limit.
The rankingEach row links to the water system’s full evidence record. Rows appear in the snapshot’s published order: a comparison of one measure (pfos, highest monitored result), not an overall safety order.
| # | Water System | PFOS, highest monitored result | On record | |
|---|---|---|---|---|
| 1 | EMMAUS BOROUGH PUBLIC WATEREmmaus, PA | 153.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 2 | CITY OF GRAND PRAIRIEGrand Prairie, TX | 82.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 3 | CITY OF OXFORDOxford, MS | 72.2 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 4 | IRONDALE WATER SYSTEMIrondale, AL | 59.4 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 5 | LAFAYETTELaFayette, GA | 56.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 6 | City of TempeTempe, AZ | 55.8 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 7 | MOSES LAKE CITY OFMoses Lake, WA | 52.2 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 8 | BROKEN ARROW MUNICIPAL AUTHORITYBroken Arrow, OK | 51.3 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 9 | AUGUSTA-RICHMOND CO WSAugusta-richmond Ws, GA | 51.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 10 | DARTMOUTH WATER DIVISIONDartmouth, MA | 50.6 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 11 | ELKO CITY OFElko, NV | 46.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 12 | NORTH MIAMI, CITY OFNorth Miami, FL | 45.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 13 | CITY OF ATWATERAtwater, CA | 45.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 14 | DOWNEY - CITY, WATER DEPT.Downey, CA | 44.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 15 | PAYSON TOWN OFPayson, AZ | 42.2 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 16 | CITY OF SACRAMENTO MAINSacramento, CA | 41.4 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 17 | CITY OF CLOVISClovis, CA | 41.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 18 | PALM SPRINGS, VILLAGE OFPalm Springs, FL | 39.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 19 | OCALA, CITY OF (2 WTPS)Ocala City (2 Wtps), FL | 39.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 20 | MDWASA/REX UTILITIESMdwasa/rex, FL | 37.4 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 21 | NATICK WATER AND SEWER DIVISIONNatick, MA | 37.3 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 22 | LAUDERHILL, CITY OFLauderhill, FL | 37.0 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 23 | TARPON SPRINGS WATER SYSTEMTarpon Springs, FL | 36.9 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 24 | EMERALD COAST UTILITIES AUTHORITY (ECUA)Emerald Coast (ecua), FL | 35.7 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round | |
| 25 | GREENSBORO, CITY OFGreensboro, NC | 35.6 ng/L (limit 4.0) | Monitored in the 2024 federal UCMR5 round |
Comparable does not mean complete.
This snapshot compares water systems on one metric. It never replaces a full system report, a city-resolution check, or a certified household test, and missing monitoring is excluded, never scored as favorable.