Most Contaminated US Water Systems: PFAS, Lead & Violations
US public water systems ranked nationally across three dimensions of drinking-water contamination, from official EPA data: PFAS forever chemicals, Lead & Copper Rule results, and EPA health-based violations. PFAS readings are historical peaks (largely EPA UCMR3, 2013-2015 – the most recent nationwide round with systems above 4 ppt); lead and violation figures are the most severe on record per system.
Quick Answer
This index links to 75 pages organized into 3 categories for easy browsing.
Highest recorded PFAS levels (ppt) – historical peaks
- Commonwealth Utilities Corp. (Saipan) (MP) – 7,000 ppt
- Artesian Water Company (DE) – 1,800 ppt
- Security WSD (CO) – 1,300 ppt
- Warminster Municipal Authority (PA) – 1,090 ppt
- Horsham Water & Sewer Authority (PA) – 1,000 ppt
- Oatman Water Company (AZ) – 730 ppt
- Warrington Township Water & Sewer Department (PA) – 666.7 ppt
- Issaquah Water System (WA) – 600 ppt
- Suffolk County Water Authority (NY) – 530 ppt
- Oakdale (MN) – 439 ppt
- Hyannis Water System (MA) – 430 ppt
- City of Tucson (AZ) – 420 ppt
- GU Waterworks Authority - Northern System (GU) – 410 ppt
- City of Cleveland Heights (OH) – 400 ppt
- Emerald Coast Utilities Authority (FL) – 380 ppt
- Calhoun (GA) – 370 ppt
- United Water PA (PA) – 363 ppt
- Widefield WSD (CO) – 330 ppt
- Rome (GA) – 330 ppt
- Sanford Water District (ME) – 290 ppt
- Liberty Water LPSCO (AZ) – 220 ppt
- Wright-Patterson AFB Area A/C (OH) – 210 ppt
- Doylestown Twp. Muni. Authority (PA) – 206.1 ppt
- City of Fountain (CO) – 190 ppt
- Bemidji (MN) – 187 ppt
Highest lead results (ppb) – Lead & Copper Rule
- SALINE COUNTY PWSD 3 (MO) – 2,750 ppb
- BAL HARBOUR VILLAGE (FL) – 1,160 ppb
- MUNCY BOROUGH WATER COMPANY (PA) – 890 ppb
- PAUL SMITHS COLLEGE (NY) – 610 ppb
- RAINBOW LAKES ESTATES (FL) – 490 ppb
- DAYTON PUBLIC WATER SYSTEM (OH) – 470 ppb
- PLEASANT VIEW WATER FAC BOARD (AR) – 370 ppb
- DUNCANNON MUNI WATER (PA) – 301 ppb
- LOMA LINDA UNIVERSITY (CA) – 216 ppb
- ALTON WATER WORKS (NH) – 210 ppb
- MOUNTAIN WATER COMPANY (VT) – 170 ppb
- TUSCARAWAS VILLAGE (OH) – 156 ppb
- GILMAN (IL) – 140 ppb
- BLACKMAN TOWNSHIP (MI) – 133 ppb
- AQUA ILLINOIS-KANKAKEE (IL) – 131 ppb
- AQUA ILLINOIS-UNIVERSITY PARK (IL) – 130 ppb
- ERIE (IL) – 130 ppb
- MOUNDS (IL) – 130 ppb
- GENOA CITY WATERWORKS (WI) – 129 ppb
- YNP-OLD FAITHFUL (WY) – 125 ppb
- FRANKLIN SYSTEM YORK WATER (PA) – 122 ppb
- KINGMAN MUNICIPAL WATER (AZ) – 110 ppb
- GREENVILLE WATER DEPT (NH) – 110 ppb
- SOUTH HOLLAND (IL) – 107 ppb
- TREASURE ISLAND (CA) – 100 ppb
Most EPA health-based violations on record
- BARNSDALL (OK) – 195 violations
- TEMPE WSC 1 (TX) – 189 violations
- WAUKESHA WATER UTILITY (WI) – 155 violations
- GRANDFIELD (OK) – 147 violations
- HOMINY (OK) – 145 violations
- CITY OF BRADY WATER SYSTEM (TX) – 126 violations
- CLEVELAND MUNICIPAL AUTHORITY (OK) – 125 violations
- MILLERSVIEW DOOLE WSC (TX) – 125 violations
- EUFAULA PWA (OK) – 123 violations
- MUSKOGEE CO. RWD #3 (OK) – 123 violations
- WAURIKA PUBLIC WORKS AUTHORITY (OK) – 116 violations
- FAIRFAX (OK) – 115 violations
- PENDLETON WATER ASSOCIATION (LA) – 114 violations
- COWETA PWA (OK) – 113 violations
- PUSHMATAHA CO. RWD #3 (OK) – 106 violations
- WEWOKA PUBLIC WORKS AUTHORITY (OK) – 105 violations
- STROUD UTILITIES AUTHORITY (OK) – 104 violations
- LAKE ST JOHN WATERWORKS DISTRICT 1 (LA) – 89 violations
- CITY OF MASON (TX) – 83 violations
- FAIRVIEW UNION WATER SYSTEM (LA) – 81 violations
- TERRE DU LAC (MO) – 81 violations
- TOWN OF FERRIDAY WATER SYSTEM (LA) – 77 violations
- CITY OF HUXLEY (TX) – 75 violations
- OIL CITY WATER WORKS (LA) – 74 violations
- KOTZEBUE MUN. WATER SYSTEM (AK) – 73 violations