PFAS "Forever Chemicals" in US Drinking Water
Tracking per- and polyfluoroalkyl substance contamination across American water systems. Data from EPA UCMR 5 monitoring, updated Q1 2026.
What are PFAS?
PFAS (per- and polyfluoroalkyl substances) are a group of synthetic chemicals that don't break down in the environment or the human body — earning them the name "forever chemicals."
Manufactured since the 1940s, PFAS have been used in non-stick cookware, firefighting foam, food packaging, stain-resistant fabrics, and countless industrial processes. They've contaminated drinking water supplies across the country, and even trace amounts are linked to serious health effects.
In April 2024, the EPA finalized the first-ever national drinking water standards for six PFAS compounds — a landmark regulation after decades of unregulated contamination. Water systems must begin monitoring by 2027 and achieve full compliance by 2029.
- Over 14,000 synthetic compounds in the PFAS family
- Called "forever chemicals" — they never break down in the environment
- Found in cookware, firefighting foam, food packaging, and textiles
- First EPA MCLs finalized April 2024 after decades of no regulation
- Full compliance required by 2029
EPA maximum contaminant levels
Finalized April 2024Linked to kidney cancer, thyroid disease, and developmental effects. Individual MCL — strictest standard.
Linked to liver damage, immune suppression, and increased cholesterol. Individual MCL — strictest standard.
Replacement for PFOA. Linked to liver and kidney toxicity. Regulated via Hazard Index.
PFHxS + PFNA + GenX + PFBS combined. Sum of individual ratios (concentration/MCL) must not exceed 1.0.
Contamination breakdown
Cities with highest PFAS contamination
Top 50 by detections & exceedances| # | City | State | Grade | Compounds | Exceeds MCL | PFOA Max | PFOS Max | Hazard Index |
|---|---|---|---|---|---|---|---|---|
| 1 | Emmaus 14K served | PA | C+ | 13 / 30 | Yes | 22.4 ppt | 153.0 ppt | 43.85 |
| 2 | Pensacola 257K served | FL | C | 12 / 30 | Yes | 25.8 ppt | 35.7 ppt | 15.38 |
| 3 | Hialeah 238K served | FL | B- | 12 / 30 | Yes | 10.2 ppt | 27.6 ppt | 9.45 |
| 4 | Georgetown 9K served | DE | F | 11 / 30 | Yes | 36.0 ppt | 14.0 ppt | 12.50 |
| 5 | Maxton 3K served | NC | C | 11 / 30 | Yes | 30.0 ppt | 6.1 ppt | 12.43 |
| 6 | Adacao 139K served | GU | B+ | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 7 | Adelup 139K served | GU | B | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 8 | Agana Heights 139K served | GU | B | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 9 | Anigua 139K served | GU | B | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 10 | Asan 139K served | GU | B | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 11 | Dededo 139K served | GU | B+ | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 12 | Pigo 139K served | GU | B | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 13 | Talofofo 139K served | GU | B+ | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 14 | Tamuning 139K served | GU | B+ | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 15 | Tumon 139K served | GU | B+ | 11 / 30 | Yes | 18.3 ppt | 135.0 ppt | 38.33 |
| 16 | Running Springs 6K served | CA | B | 11 / 30 | Yes | 15.9 ppt | 236.5 ppt | 63.10 |
| 17 | Ambler 20K served | PA | F | 11 / 30 | Yes | 15.3 ppt | 13.7 ppt | 7.25 |
| 18 | Doylestown 18K served | PA | D | 11 / 30 | Yes | 14.6 ppt | 13.4 ppt | 7.00 |
| 19 | North Bay Village 8K served | FL | B+ | 11 / 30 | Yes | 14.2 ppt | 43.3 ppt | 14.38 |
| 20 | Clarkstown (T) 270K served | NY | B- | 11 / 30 | Yes | 14.0 ppt | 6.8 ppt | 5.20 |
| 21 | Miami 2.4M served | FL | F | 11 / 30 | Yes | 14.0 ppt | 37.4 ppt | 12.85 |
| 22 | Pewaukee 17K served | WI | F | 11 / 30 | Yes | 8.5 ppt | 12.0 ppt | 5.13 |
| 23 | Pflugerville 63K served | TX | C+ | 11 / 30 | Yes | 6.3 ppt | 14.4 ppt | 5.17 |
| 24 | Coupland 40K served | TX | C | 11 / 30 | Yes | 5.9 ppt | 12.4 ppt | 4.58 |
| 25 | Great Bend 16K served | KS | F | 11 / 30 | Yes | 5.2 ppt | 11.0 ppt | 4.05 |
| 26 | Warrenton 30K served | VA | F | 10 / 30 | Yes | 44.6 ppt | 31.1 ppt | 18.93 |
| 27 | Payson 25K served | AZ | F | 10 / 30 | Yes | 40.9 ppt | 42.2 ppt | 20.77 |
| 28 | Tempe 165K served | AZ | D+ | 10 / 30 | Yes | 38.7 ppt | 55.8 ppt | 23.63 |
| 29 | Atwater 29K served | CA | B+ | 10 / 30 | Yes | 33.0 ppt | 45.0 ppt | 19.50 |
| 30 | Ridgewood Twp-0251 62K served | NJ | D+ | 10 / 30 | Yes | 31.4 ppt | 13.8 ppt | 11.30 |
| 31 | Norristown 99K served | PA | F | 10 / 30 | Yes | 30.8 ppt | 57.9 ppt | 22.18 |
| 32 | Hohokus Boro-0228 4K served | NJ | B+ | 10 / 30 | Yes | 30.4 ppt | 21.0 ppt | 12.85 |
| 33 | New Castle (T) 17K served | NY | B | 10 / 30 | Yes | 27.8 ppt | 106.0 ppt | 33.45 |
| 34 | Waldwick Boro-0264 10K served | NJ | F | 10 / 30 | Yes | 23.3 ppt | 10.2 ppt | 8.38 |
| 35 | Harrisburg 248K served | PA | F | 10 / 30 | Yes | 22.3 ppt | 11.4 ppt | 8.43 |
| 36 | Richboro 37K served | PA | F | 10 / 30 | Yes | 19.6 ppt | 23.0 ppt | 10.65 |
| 37 | Clovis 132K served | CA | F | 10 / 30 | Yes | 18.0 ppt | 41.0 ppt | 14.75 |
| 38 | Grand Terrace 20K served | CA | B | 10 / 30 | Yes | 18.0 ppt | 19.0 ppt | 9.25 |
| 39 | Hillsdale Boro-0227 793K served | NJ | D | 10 / 30 | Yes | 17.2 ppt | 14.1 ppt | 7.83 |
| 40 | Montvale Boro-0236 793K served | NJ | D | 10 / 30 | Yes | 17.2 ppt | 14.1 ppt | 7.83 |
| 41 | Park Ridge Boro-0247 16K served | NJ | C+ | 10 / 30 | Yes | 17.2 ppt | 14.1 ppt | 7.83 |
| 42 | Saddle River Boro-0258 16K served | NJ | C+ | 10 / 30 | Yes | 17.2 ppt | 14.1 ppt | 7.83 |
| 43 | Woodcliff Lake Boro-0268 793K served | NJ | D | 10 / 30 | Yes | 17.2 ppt | 14.1 ppt | 7.83 |
| 44 | Bryn Mawr 1.1M served | PA | F | 10 / 30 | Yes | 16.2 ppt | 21.5 ppt | 9.43 |
| 45 | Fresno 625K served | CA | F | 10 / 30 | Yes | 16.0 ppt | 30.0 ppt | 11.50 |
| 46 | Montebello 42K served | CA | B | 10 / 30 | Yes | 16.0 ppt | 53.0 ppt | 17.25 |
| 47 | Telford 8K served | PA | B | 10 / 30 | Yes | 14.9 ppt | 15.2 ppt | 7.53 |
| 48 | North Wales 97K served | PA | F | 10 / 30 | Yes | 13.0 ppt | 11.1 ppt | 6.03 |
| 49 | North Hempstead (T) 120K served | NY | F | 10 / 30 | Yes | 12.0 ppt | 6.9 ppt | 4.72 |
| 50 | Colorado Springs 567K served | CO | F | 10 / 30 | Yes | 10.5 ppt | 15.8 ppt | 6.58 |
Worried about PFAS in your water?
Check your city's detailed PFAS report — or browse our filter guide for NSF-certified options that remove forever chemicals.