Tap water · contaminant or rule

Total Haloacetic Acids (HAA5) in drinking water

The community water systems with a health-based violation of Total Haloacetic Acids (HAA5) on EPA's record since Oct. 23, 2023, most people served first. EPA's file dated Oct. 23, 2026.

613

613 systems serving 2,880,472 people in 38 states and territories.

Health-based violations, in EPA's words: “Violations of maximum contaminant levels (MCLs) or maximum residual disinfectant levels (MRDLs), which specify the highest concentrations of contaminants or disinfectants, respectively, allowed in drinking water; or of treatment technique (TT) rules, which specify required processes intended to reduce the amounts of contaminants in drinking water. MCLs, MRDLs, and treatment technique rules are all health-based drinking water standards.”

By state

Systems

AKRON CITY PWS280,000 peopleSummit (county), Ohio · 1 violation, latest July 1, 2025 · highest 0.062 MG/L
CITY OF JACKSON189,673 peopleJACKSON, Mississippi · 3 violations, latest April 1, 2025 · highest 0.069 MG/L (limit 0.06 MG/L)
SPRINGFIELD WATER AND SEWER COMMISSION169,170 peopleSPRINGFIELD, Massachusetts · 11 violations, latest April 1, 2026
BJW&SA (SC0720003)164,829 peopleBeaufort (county), South Carolina · 1 violation, latest Oct. 1, 2023 · highest 0.069 MG/L (limit 0.06 MG/L)
VALDOSTA48,959 peopleVALDOSTA, Georgia · 6 violations, latest April 1, 2026 · highest 0.072 MG/L (limit 0.06 MG/L)
PINELLAS PARK WATER DEPT48,939 peoplePINELLAS PARK, Florida · 3 violations, latest Oct. 1, 2024 · highest 1493.175 UG/L
OILDALE MWC45,315 peopleKern (county), California · 3 violations, latest Jan. 1, 2024 · highest 0.0737 MG/L (limit 0.06 MG/L)
EAST NILES CSD32,517 peopleKern (county), California · 2 violations, latest Jan. 1, 2024 · highest 0.0705 MG/L (limit 0.06 MG/L)
DEKALB-JACKSON WATER SUPPLY DISTRICT32,421 peopleJackson (county), Alabama · 7 violations, latest July 1, 2025 · highest 0.099 MG/L (limit 0.06 MG/L)
PENDER COUNTY UTILITIES32,302 peopleBURGAW, North Carolina · 1 violation, latest Jan. 1, 2024 · highest 0.061 MG/L (limit 0.06 MG/L)
WARREN COUNTY UTILITY DISTRICT29,055 peopleMCMINNVILLE, Tennessee · 1 violation, latest July 1, 2024 · highest 0.06108 MG/L (limit 0.06 MG/L)
TOCCOA28,711 peopleTOCCOA, Georgia · 1 violation, latest April 1, 2024 · highest 0.064 MG/L (limit 0.06 MG/L)
CITY OF JACKSON-MADDOX RD.28,098 peopleJACKSON, Mississippi · 2 violations, latest July 1, 2025 · highest 0.063 MG/L (limit 0.06 MG/L)
ASHEBORO, CITY OF27,819 peopleASHEBORO, North Carolina · 1 violation, latest Jan. 1, 2025 · highest 0.065 MG/L (limit 0.06 MG/L)
FRANKLIN COUNTY WATER & SEWER26,060 peopleFRANKLINTON, North Carolina · 2 violations, latest July 1, 2026 · highest 0.063 MG/L (limit 0.06 MG/L)
DAYTON WATER DEPT25,054 peopleDAYTON, Tennessee · 1 violation, latest Jan. 1, 2024 · highest 0.0604 MG/L (limit 0.06 MG/L)
LAKE UTILITY SERVICES INC NORTH (8 WPS)24,798 peopleCLERMONT, Florida · 4 violations, latest Oct. 1, 2021 · highest 73.52 UG/L
BALDWIN COUNTY23,067 peopleBaldwin (county), Georgia · 11 violations, latest Jan. 1, 2026 · highest 0.072 MG/L (limit 0.06 MG/L)
HIGHLAND S & W AUTH BEAVERDAM22,617 peopleCambria (county), Pennsylvania · 1 violation, latest Jan. 1, 2003 · highest 0.06524375 MG/L
THOMSON-MCDUFFIE CO W&S COMM21,312 peopleTHOMSON, Georgia · 1 violation, latest July 1, 2025 · highest 0.061 MG/L (limit 0.06 MG/L)
MCALESTER PWA18,206 peoplePittsburg (county), Oklahoma · 3 violations, latest Oct. 1, 2020 · highest 0.069 MG/L (limit 0.06 MG/L)
CITY OF NEDERLAND18,157 peopleJefferson (county), Texas · 4 violations, latest Jan. 1, 2026 · highest 0.095 MG/L (limit 0.06 MG/L)
KENSICO WATER DISTRICT17,917 peopleMOUNT PLEASANT (T), New York · 2 violations, latest Jan. 1, 2022 · highest 0.071 MG/L (limit 0.06 MG/L)
SWANSEA WATER DISTRICT17,375 peopleSWANSEA, Massachusetts · 4 violations, latest July 1, 2025
POPLAR BLUFF PWS17,043 peoplePOPLAR BLUFF, Missouri · 1 violation, latest July 1, 2025 · highest 61.18 UG/L (limit 60 UG/L)
FENTRESS COUNTY U.D.16,845 peopleFentress (county), Tennessee · 3 violations, latest July 1, 2024 · highest 0.07085 MG/L (limit 0.06 MG/L)
HARRISON CO WATER ASSOCIATION16,736 peopleHarrison (county), Kentucky · 2 violations, latest April 1, 2024 · highest 0.067 MG/L (limit 0.06 MG/L)
LOWNDES CO.-NORTH LOWNDES CO. WS16,656 peopleLAKE PARK, Georgia · 11 violations, latest April 1, 2026 · highest 0.129 MG/L (limit 0.06 MG/L)
DURANT UTILITIES AUTHORITY15,545 peopleBryan (county), Oklahoma · 2 violations, latest April 1, 2024 · highest 0.065 MG/L (limit 0.06 MG/L)
TEQUESTA PWS, VILLAGE OF15,500 peopleTEQUESTA, Florida · 1 violation, latest Oct. 1, 2004 · highest 61.96 UG/L
MONTGOMERY COUNTY WATER SYSTEM15,362 peopleMT GILEAD, North Carolina · 4 violations, latest July 1, 2025 · highest 0.078 MG/L (limit 0.06 MG/L)
EAST CEDAR CREEK FWSD BROOKSHIRE14,823 peopleHenderson (county), Texas · 1 violation, latest April 1, 2025 · highest 0.061 MG/L (limit 0.06 MG/L)
EDGECOMBE WATER & SEWER DISTRICT14,485 peopleTARBORO, North Carolina · 4 violations, latest April 1, 2025 · highest 0.07 MG/L (limit 0.06 MG/L)
OKMULGEE PWA13,495 peopleOkmulgee (county), Oklahoma · 7 violations, latest Jan. 1, 2026 · highest 0.076 MG/L (limit 0.06 MG/L)
WILDERNESS13,274 peopleOrange (county), Virginia · 4 violations, latest Oct. 1, 2024 · highest 0.064 MG/L (limit 0.06 MG/L)
CITY OF SOPCHOPPY12,998 peopleSOPCHOPPY, Florida · 1 violation, latest April 1, 2024 · highest 61.76 UG/L
LINDSAY, CITY OF12,659 peopleLINDSAY, California · 7 violations, latest April 1, 2026 · highest 0.0692 MG/L (limit 0.06 MG/L)
OTTAWA, CITY OF12,604 peopleOTTAWA, Kansas · 1 violation, latest July 1, 2024 · highest 0.061 MG/L (limit 0.06 MG/L)
EAST CASEY CO WATER DISTRICT12,460 peopleCasey (county), Kentucky · 2 violations, latest April 1, 2026 · highest 0.065 MG/L (limit 0.06 MG/L)
GLADSTONE, CITY OF12,121 peopleClackamas (county), Oregon · 4 violations, latest Oct. 1, 2025 · highest 0.104 MG/L (limit 0.06 MG/L)
R.C. WILLIS WTP (CITY OF PALATKA)11,900 peoplePALATKA, Florida · 2 violations, latest Jan. 1, 2019 · highest 65.6 UG/L
CCWD - EBBETTS PASS11,545 peopleCalaveras (county), California · 4 violations, latest Oct. 1, 2022 · highest 62.75 UG/L (limit 60 UG/L)
RATTLESNAKE RIDGE WATER DISTRICT11,397 peopleCarter (county), Kentucky · 1 violation, latest July 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
SOUTHERN OKLA WATER CORP11,250 peopleCarter (county), Oklahoma · 4 violations, latest April 1, 2026 · highest 0.076 MG/L (limit 0.06 MG/L)
APPALACHIAN STATE UNIV WTP11,150 peopleBOONE, North Carolina · 1 violation, latest Jan. 1, 2025 · highest 0.077 MG/L (limit 0.06 MG/L)
CASITAS MUNICIPAL WATER DIST11,005 peopleVentura (county), California · 1 violation, latest Oct. 1, 2023 · highest 0.061 MG/L (limit 0.06 MG/L)
HARTSVILLE-TROUSDALE W&S U.D.10,562 peopleHARTSVILLE, Tennessee · 3 violations, latest Jan. 1, 2025 · highest 0.06648 MG/L (limit 0.06 MG/L)
ROGERS CO RWD # 3 LAKE PLANT10,470 peopleRogers (county), Oklahoma · 8 violations, latest April 1, 2023 · highest 0.07 MG/L (limit 0.06 MG/L)
PORT SULPHUR WATER DISTRICT10,308 peoplePlaquemines Parish (county), Louisiana · 6 violations, latest April 1, 2026 · highest 0.089 MG/L (limit 0.06 MG/L)
WOODFIN SANITARY WATER AND SEWER10,122 peopleWEAVERVILLE, North Carolina · 1 violation, latest Oct. 1, 2024 · highest 0.061 MG/L (limit 0.06 MG/L)
WATER & SEWER COMMISSION 4 OF ST MARY9,709 peopleSt. Mary Parish (county), Louisiana · 3 violations, latest Jan. 1, 2025 · highest 0.073 MG/L (limit 0.06 MG/L)
CUMBERLAND FALLS HIGHWAY WATER DISTRICT9,498 peopleWhitley (county), Kentucky · 3 violations, latest Jan. 1, 2024 · highest 0.064 MG/L (limit 0.06 MG/L)
PARSONS, CITY OF9,479 peoplePARSONS, Kansas · 5 violations, latest April 1, 2024 · highest 0.091 MG/L (limit 0.06 MG/L)
COWETA PWA9,450 peopleWagoner (county), Oklahoma · 11 violations, latest Jan. 1, 2026 · highest 0.131 MG/L (limit 0.06 MG/L)
LEFLORE CO. RWD #149,077 peopleLe Flore (county), Oklahoma · 2 violations, latest Jan. 1, 2023 · highest 0.062 MG/L (limit 0.06 MG/L)
GUERNSEY CO. WATER DEPT.8,891 peopleGuernsey (county), Ohio · 1 violation, latest April 1, 2024 · highest 0.063 MG/L (limit 0.06 MG/L)
GEORGETOWN WATER DEPARTMENT8,766 peopleGEORGETOWN, Massachusetts · 3 violations, latest Oct. 1, 2025
BYRDSTOWN WATER DEPARTMENT8,658 peopleBYRDSTOWN, Tennessee · 4 violations, latest Jan. 1, 2025 · highest 0.08375 MG/L (limit 0.06 MG/L)
TOWN OF NORTH EAST8,600 peopleCecil (county), Maryland · 5 violations, latest Jan. 1, 2026 · highest 80 UG/L (limit 60 UG/L)
EBENSBURG BORO MUNI AUTH8,500 peopleCambria (county), Pennsylvania · 4 violations, latest Jan. 1, 2023 · highest 0.099 MG/L
SO ANDERSON WATER DISTRICT8,417 peopleAnderson (county), Kentucky · 2 violations, latest April 1, 2024 · highest 0.07 MG/L (limit 0.06 MG/L)
OKMULGEE CO. RWD #6 (HECTORVILLE)8,370 peopleOkmulgee (county), Oklahoma · 15 violations, latest April 1, 2025 · highest 0.102 MG/L (limit 0.06 MG/L)
MINOR HILL WATER UTILITY DISTRICT8,364 peopleGiles (county), Tennessee · 1 violation, latest July 1, 2023 · highest 0.0646 MG/L (limit 0.06 MG/L)
CITY OF FRANKLIN WATER SUPPLY8,325 peopleSt. Mary Parish (county), Louisiana · 4 violations, latest Oct. 1, 2024 · highest 0.069 MG/L (limit 0.06 MG/L)
BRYAN COUNTY RURAL WATER DISTRICT #58,325 peopleBryan (county), Oklahoma · 6 violations, latest Jan. 1, 2023 · highest 0.07 MG/L (limit 0.06 MG/L)
KNOX COUNTY UTILITY COMMISSION8,313 peopleKnox (county), Kentucky · 2 violations, latest July 1, 2025 · highest 0.069 MG/L (limit 0.06 MG/L)
SALEM WATER WORKS8,200 peopleSALEM, Indiana · 6 violations, latest Oct. 1, 2021 · highest 98.6 UG/L (limit 60 UG/L)
HEARD COUNTY WATER AUTHORITY8,172 peopleHeard (county), Georgia · 3 violations, latest Jan. 1, 2024 · highest 0.072 MG/L (limit 0.06 MG/L)
SPRINGFIELD, CITY OF8,075 peopleSPRINGFIELD, Florida · 4 violations, latest July 1, 2024 · highest 87.275 UG/L
BOYERTOWN MUNI AUTH8,000 peopleBerks (county), Pennsylvania · 3 violations, latest April 1, 2026 · highest 0.064 MG/L
TAMAQUA AREA WATER AUTHORITY8,000 peopleSchuylkill (county), Pennsylvania · 4 violations, latest July 1, 2024 · highest 0.075 MG/L
ASHLAND WATER UTILITY8,000 peopleASHLAND, Wisconsin · 2 violations, latest Jan. 1, 2024 · highest 69.5 UG/L (limit 60.5 UG/L)
PISMO BEACH WATER DEPARTMENT7,944 peopleSan Luis Obispo (county), California · 3 violations, latest Jan. 1, 2024 · highest 0.067 MG/L (limit 0.06 MG/L)
POTEAU PWA7,939 peopleLe Flore (county), Oklahoma · 7 violations, latest Oct. 1, 2025 · highest 0.069 MG/L (limit 0.06 MG/L)
ST MARY WATER & SEWER COMM #37,828 peopleSt. Mary Parish (county), Louisiana · 1 violation, latest Jan. 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
WYTHEVILLE, TOWN OF7,804 peopleWythe (county), Virginia · 2 violations, latest July 1, 2023 · highest 69 UG/L (limit 60 UG/L)
VANDALIA7,616 peopleVANDALIA, Illinois · 1 violation, latest July 1, 2024 · highest 0.062 MG/L (limit 0.06 MG/L)
EMPORIA, CITY OF7,594 peopleEMPORIA CITY, Virginia · 6 violations, latest July 1, 2023 · highest 91 UG/L (limit 60 UG/L)
NEW PALTZ (VILLAGE) WATER DIST7,523 peopleNEW PALTZ (T), New York · 4 violations, latest April 1, 2025 · highest 0.06491 MG/L (limit 0.06 MG/L)
MORGAN COUNTY WATER DISTRICT7,502 peopleMorgan (county), Kentucky · 2 violations, latest Oct. 1, 2025 · highest 0.065 MG/L (limit 0.06 MG/L)
FRUITLAND CITY OF7,458 peoplePayette (county), Idaho · 3 violations, latest Oct. 1, 2024 · highest 0.084 MG/L (limit 0.06 MG/L)
CITY OF PERRY7,281 peoplePERRY, Florida · 2 violations, latest Jan. 1, 2025 · highest 72 UG/L
NORTH GREENE UTILITIES, INCORPORATED7,035 peopleGREENEVILLE, Tennessee · 3 violations, latest July 1, 2025 · highest 0.0685 MG/L (limit 0.06 MG/L)
CITY OF RICHLAND7,000 peopleRICHLAND, Mississippi · 2 violations, latest April 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
IDABEL PWA6,952 peopleMcCurtain (county), Oklahoma · 20 violations, latest April 1, 2026 · highest 0.082 MG/L (limit 0.06 MG/L)
CITY OF CARTHAGE6,770 peoplePanola (county), Texas · 4 violations, latest July 1, 2025 · highest 0.076 MG/L (limit 0.06 MG/L)
LYON COUNTY WATER DISTRICT6,744 peopleLyon (county), Kentucky · 3 violations, latest April 1, 2025 · highest 0.072 MG/L (limit 0.06 MG/L)
RALEIGH COUNTY PSD ARNETT6,663 peopleARNETT, West Virginia · 9 violations, latest July 1, 2025 · highest 80 UG/L (limit 60 UG/L)
HUNTINGBURG MUNICIPAL WATER6,526 peopleHUNTINGBURG, Indiana · 1 violation, latest Jan. 1, 2024 · highest 60.6 UG/L (limit 60 UG/L)
WASHINGTON6,490 peopleWASHINGTON, Georgia · 4 violations, latest July 1, 2025 · highest 0.067 MG/L (limit 0.06 MG/L)
INTRACOASTAL WATER SYSTEM WEST6,489 peopleIberville Parish (county), Louisiana · 5 violations, latest July 1, 2023 · highest 0.084 MG/L (limit 0.06 MG/L)
VINITA UTILITIES AUTHORITY6,472 peopleCraig (county), Oklahoma · 3 violations, latest April 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
MADISON6,427 peopleMADISON, Georgia · 3 violations, latest Oct. 1, 2024 · highest 0.062 MG/L (limit 0.06 MG/L)
GULF COUNTY WATER DEPARTMENT6,287 peoplePORT ST. JOE, Florida · 1 violation, latest Jan. 1, 2024 · highest 63.925 UG/L
UNION COUNTY WATER DISTRICT6,117 peopleUnion (county), Kentucky · 3 violations, latest Jan. 1, 2026 · highest 0.083 MG/L (limit 0.06 MG/L)
VENTURA RIVER WATER DISTRICT6,100 peopleVentura (county), California · 2 violations, latest Oct. 1, 2023 · highest 0.069 MG/L (limit 0.06 MG/L)
TECUMSEH UTILITY AUTHORITY6,098 peoplePottawatomie (county), Oklahoma · 7 violations, latest April 1, 2026 · highest 0.066 MG/L (limit 0.06 MG/L)
WESTCHESTER COUNTY WD #36,000 peopleGREENBURGH (T), New York · 2 violations, latest Jan. 1, 2022 · highest 0.067 MG/L (limit 0.06 MG/L)
WOODSTOCK, TOWN OF5,955 peopleShenandoah (county), Virginia · 6 violations, latest April 1, 2025 · highest 79 UG/L (limit 60 UG/L)
SOUTH TOLEDO BEND WATER DISTRICT5,943 peopleSabine Parish (county), Louisiana · 1 violation, latest July 1, 2024 · highest 0.07 MG/L (limit 0.06 MG/L)
NASHVILLE, TOWN OF5,900 peopleNASHVILLE, North Carolina · 2 violations, latest Jan. 1, 2025 · highest 0.061 MG/L (limit 0.06 MG/L)
MEXICO BEACH, CITY OF5,888 peopleMEXICO BEACH, Florida · 4 violations, latest July 1, 2024 · highest 131 UG/L
VILLAGE OF INDIANTOWN5,847 peopleINDIANTOWN, Florida · 3 violations, latest Jan. 1, 2026 · highest 126.0617 UG/L
HIGH SPRINGS WTP5,795 peopleHIGH SPRINGS, Florida · 1 violation, latest April 1, 2015 · highest 81.57 UG/L
BLOOMFIELD WATER & SEWER DEPT5,771 peopleNelson (county), Kentucky · 1 violation, latest July 1, 2023 · highest 0.061 MG/L (limit 0.06 MG/L)
WILMORE WATER WORKS5,762 peopleJessamine (county), Kentucky · 1 violation, latest April 1, 2024 · highest 0.066 MG/L (limit 0.06 MG/L)
BUCKINGHAM CO WATER SYSTEM5,759 peopleBuckingham (county), Virginia · 4 violations, latest July 1, 2025 · highest 0.068 MG/L (limit 0.06 MG/L)
MAGNOLIA - TOWN & COUNTRY SERVICE5,715 peopleOuachita Parish (county), Louisiana · 1 violation, latest April 1, 2026 · highest 0.065 MG/L (limit 0.06 MG/L)
TRACY CITY WATER SYSTEM5,692 peopleTRACY CITY, Tennessee · 4 violations, latest July 1, 2025 · highest 0.07315 MG/L (limit 0.06 MG/L)
CREEK CO RWD # 15,675 peopleCreek (county), Oklahoma · 2 violations, latest April 1, 2025 · highest 0.083 MG/L (limit 0.06 MG/L)
WARREN COUNTY U.D. #25,611 peopleSPENCER, Tennessee · 10 violations, latest April 1, 2026 · highest 0.12568 MG/L (limit 0.06 MG/L)
CALISTOGA, CITY OF5,610 peopleCALISTOGA, California · 3 violations, latest July 1, 2023 · highest 74.4 UG/L (limit 60 UG/L)
FAYETTE WATER COMPANY5,608 peopleFayette (county), Illinois · 3 violations, latest April 1, 2026 · highest 0.07 MG/L (limit 0.06 MG/L)
HUGO MUNICIPAL AUTHORITY5,536 peopleChoctaw (county), Oklahoma · 5 violations, latest Oct. 1, 2025 · highest 0.063 MG/L (limit 0.06 MG/L)
CITY OF MARLIN5,516 peopleFalls (county), Texas · 8 violations, latest April 1, 2026 · highest 0.153 MG/L (limit 0.06 MG/L)
LONGTOWN RW&SD #1 (PITTSBURG CO.)5,444 peoplePittsburg (county), Oklahoma · 2 violations, latest Jan. 1, 2026 · highest 0.063 MG/L (limit 0.06 MG/L)
FALL CREEK FALLS U.D.5,434 peopleBledsoe (county), Tennessee · 1 violation, latest July 1, 2024 · highest 0.0655 MG/L (limit 0.06 MG/L)
HUSTONVILLE WATER WORKS5,420 peopleLincoln (county), Kentucky · 1 violation, latest Oct. 1, 2024 · highest 0.062 MG/L (limit 0.06 MG/L)
FRENCHBURG WATER COMPANY5,401 peopleMenifee (county), Kentucky · 2 violations, latest April 1, 2024 · highest 0.064 MG/L (limit 0.06 MG/L)
WATER MGMT SERVICES (ST. GEORGE ISLAND)5,272 peopleST GEORGE ISLAND, Florida · 1 violation, latest April 1, 2024 · highest 68.1225 UG/L
TOWN OF GREENWOOD WATER SYSTEM5,205 peopleCaddo Parish (county), Louisiana · 1 violation, latest April 1, 2023 · highest 0.068 MG/L (limit 0.06 MG/L)
EAST JOHNSON CO WATER ASSN5,200 peopleJohnson, Pope (county), Arkansas · 1 violation, latest Oct. 1, 2025 · highest 61 UG/L (limit 60 UG/L)
ST. CLAIRSVILLE, CITY OF PWS5,097 peopleBelmont (county), Ohio · 1 violation, latest Jan. 1, 2024 · highest 0.065 MG/L (limit 0.06 MG/L)
WOOSTER WATERWORKS5,000 peopleFaulkner (county), Arkansas · 1 violation, latest Oct. 1, 2023 · highest 61 UG/L (limit 60 UG/L)
MIDLAND-LONACONING5,000 peopleAllegany (county), Maryland · 1 violation, latest April 1, 2025 · highest 63 UG/L (limit 60 UG/L)
PARIS WATERWORKS4,935 peopleLogan (county), Arkansas · 2 violations, latest Jan. 1, 2026 · highest 67 UG/L (limit 60 UG/L)
PUSHMATAHA CO. RWD #34,825 peoplePushmataha (county), Oklahoma · 15 violations, latest April 1, 2026 · highest 0.088 MG/L (limit 0.06 MG/L)
LAWRENCEVILLE, TOWN OF4,806 peopleBrunswick (county), Virginia · 4 violations, latest Oct. 1, 2024 · highest 0.094 MG/L (limit 0.06 MG/L)
LEFLORE CO. RWD #24,700 peopleLe Flore (county), Oklahoma · 7 violations, latest Jan. 1, 2026 · highest 0.072 MG/L (limit 0.06 MG/L)
JEFFERSON COUNTY WCID 104,605 peopleJefferson (county), Texas · 4 violations, latest Jan. 1, 2026 · highest 0.084 MG/L (limit 0.06 MG/L)
RALEIGH COUNTY MEM AIRPORT4,587 peopleBEAVER, West Virginia · 8 violations, latest July 1, 2025 · highest 71 UG/L (limit 60 UG/L)
BERRYVILLE, TOWN OF4,574 peopleClarke (county), Virginia · 8 violations, latest Jan. 1, 2025 · highest 69 UG/L (limit 60 UG/L)
TOWN OF MAMOU WATER SYSTEM4,559 peopleEvangeline Parish (county), Louisiana · 10 violations, latest Jan. 1, 2023 · highest 0.074 MG/L (limit 0.06 MG/L)
PROVIDENCE WATER WORKS4,538 peopleWebster (county), Kentucky · 16 violations, latest April 1, 2026 · highest 0.082 MG/L (limit 0.06 MG/L)
NORTHWEST CLAY COUNTY UTILITY4,437 peopleMOSS, Tennessee · 4 violations, latest Oct. 1, 2025 · highest 0.06398 MG/L (limit 0.06 MG/L)
TOWN OF MANY WATER SYSTEM4,428 peopleSabine Parish (county), Louisiana · 5 violations, latest April 1, 2022 · highest 0.112 MG/L (limit 0.06 MG/L)
MCCALL CITY OF4,423 peopleValley (county), Idaho · 4 violations, latest July 1, 2024 · highest 0.085 MG/L (limit 0.06 MG/L)
BUFFALO, CITY OF4,419 peopleBUFFALO, Wyoming · 6 violations, latest July 1, 2024 · highest 0.08 MG/L (limit 0.06 MG/L)
WAGONER CO. RWD #94,363 peopleWagoner (county), Oklahoma · 14 violations, latest April 1, 2026 · highest 0.086 MG/L (limit 0.06 MG/L)
PARKER, CITY OF WATER SYSTEM4,358 peoplePARKER, Florida · 1 violation, latest Oct. 1, 2023 · highest 66.8 UG/L
WEST EARL WATER AUTHORITY4,327 peopleLancaster (county), Pennsylvania · 1 violation, latest Oct. 1, 2024 · highest 0.061 MG/L
NORWOOD, TOWN OF4,323 peopleNORWOOD, North Carolina · 3 violations, latest April 1, 2025 · highest 0.065 MG/L (limit 0.06 MG/L)
UNION CITY MUNICIPAL AUTHORITY4,295 peopleErie (county), Pennsylvania · 2 violations, latest Oct. 1, 2025 · highest 0.061 MG/L
OSAWATOMIE, CITY OF4,280 peopleOSAWATOMIE, Kansas · 3 violations, latest July 1, 2024 · highest 0.066 MG/L (limit 0.06 MG/L)
LOUISA COUNTY WATER AUTHORITY4,254 peopleLouisa (county), Virginia · 2 violations, latest Oct. 1, 2025 · highest 66 UG/L (limit 60 UG/L)
JACKSON TWP WATER AUTH4,236 peopleCambria (county), Pennsylvania · 2 violations, latest April 1, 2022 · highest 0.107 MG/L
MONTEAGLE PUBLIC UTILITY BOARD4,179 peopleMONTEAGLE, Tennessee · 4 violations, latest April 1, 2024 · highest 0.06328 MG/L (limit 0.06 MG/L)
BALDWIN4,160 peopleBALDWIN, Georgia · 2 violations, latest July 1, 2024 · highest 0.063 MG/L (limit 0.06 MG/L)
SHAWNEE CO RWD 1C4,160 peopleAUBURN, Kansas · 5 violations, latest Jan. 1, 2025 · highest 0.073 MG/L (limit 0.06 MG/L)
CLIFTON WATER DEPT4,110 peopleCLIFTON, Tennessee · 1 violation, latest April 1, 2024 · highest 0.06275 MG/L (limit 0.06 MG/L)
RAYBURN COUNTRY MUD4,062 peopleJasper (county), Texas · 21 violations, latest April 1, 2026 · highest 0.079 MG/L (limit 0.06 MG/L)
TOWN OF VIVIAN WATER SYSTEM4,050 peopleCaddo Parish (county), Louisiana · 3 violations, latest Oct. 1, 2023 · highest 0.069 MG/L (limit 0.06 MG/L)
MILLERSVIEW DOOLE WSC3,987 peopleConcho (county), Texas · 7 violations, latest April 1, 2026 · highest 0.1 MG/L (limit 0.06 MG/L)
RAVENCLIFF MCGRAWS SAULSVILLE PSD3,967 peopleMCGRAWS, West Virginia · 2 violations, latest April 1, 2023 · highest 77 UG/L (limit 60 UG/L)
WEST WISE SUD3,909 peopleWise (county), Texas · 4 violations, latest April 1, 2026 · highest 0.085 MG/L (limit 0.06 MG/L)
THE CONSOLIDATED WSC CENTRAL SYSTEM3,878 peopleHouston (county), Texas · 4 violations, latest Jan. 1, 2025 · highest 0.1 MG/L (limit 0.06 MG/L)
LEFLORE CO. RWD #183,870 peopleLe Flore (county), Oklahoma · 3 violations, latest Oct. 1, 2025 · highest 0.067 MG/L (limit 0.06 MG/L)
CITY OF CLYDE3,820 peopleCallahan (county), Texas · 4 violations, latest April 1, 2025 · highest 0.074 MG/L (limit 0.06 MG/L)
TOWN OF FERRIDAY WATER SYSTEM3,816 peopleConcordia Parish (county), Louisiana · 50 violations, latest Oct. 1, 2022 · highest 149 UG/L (limit 60 UG/L)
OCEANA COMMUNITY OF3,796 peopleOCEANA, West Virginia · 13 violations, latest Jan. 1, 2026 · highest 129 UG/L (limit 60 UG/L)
Eveleth3,770 peopleSt. Louis (county), Minnesota · 4 violations, latest April 1, 2026 · highest 0.0613 MG/L
CITY OF EMORY3,762 peopleRains (county), Texas · 3 violations, latest April 1, 2026 · highest 0.069 MG/L (limit 0.06 MG/L)
LOGAN CO PSD-GREENVILLE SYSTEM3,742 peopleGREENVILLE, West Virginia · 4 violations, latest Jan. 1, 2025 · highest 64 UG/L (limit 60 UG/L)
SOMERVELL COUNTY WATER DISTRICT3,666 peopleSomervell (county), Texas · 5 violations, latest Jan. 1, 2026 · highest 0.08 MG/L (limit 0.06 MG/L)
MARION COUNTY PUBLIC WATER AUTHORITY3,660 peopleGUIN, Alabama · 4 violations, latest July 1, 2023 · highest 0.074 MG/L (limit 0.06 MG/L)
HUNTSVILLE WATERWORKS3,648 peopleMadison (county), Arkansas · 1 violation, latest Jan. 1, 2026 · highest 63 UG/L (limit 60 UG/L)
PLEASANT VALLEY WATER AUTH3,630 peopleFayette (county), Pennsylvania · 3 violations, latest April 1, 2022 · highest 0.063 MG/L
LOMETA REGIONAL WATER3,609 peopleLampasas (county), Texas · 6 violations, latest April 1, 2025 · highest 0.08 MG/L (limit 0.06 MG/L)
SOUTH RAINS SUD3,594 peopleRains (county), Texas · 3 violations, latest April 1, 2026 · highest 0.068 MG/L (limit 0.06 MG/L)
TROY, TOWN OF3,591 peopleTROY, North Carolina · 1 violation, latest July 1, 2025 · highest 0.065 MG/L (limit 0.06 MG/L)
THREE COUNTY PWD3,575 peopleMadison (county), Illinois · 3 violations, latest April 1, 2026 · highest 0.068 MG/L (limit 0.06 MG/L)
HAHIRA3,572 peopleHAHIRA, Georgia · 17 violations, latest Oct. 1, 2025 · highest 0.087 MG/L (limit 0.06 MG/L)
GREATER HARRISON PSD LOST CREEK MT CLARE3,536 peopleWEST MILFORD, West Virginia · 2 violations, latest April 1, 2023 · highest 70 UG/L (limit 60 UG/L)
STOKES REGIONAL WATER CORP3,530 peopleSTOKES, North Carolina · 1 violation, latest Jan. 1, 2024 · highest 0.068 MG/L (limit 0.06 MG/L)
FGUA - PLANTATION BAY WTP3,522 peopleBUNNELL, Florida · 6 violations, latest Jan. 1, 2006 · highest 124.1 UG/L
DESOTO COUNTY WATER SYSTEM3,518 peopleARCADIA, Florida · 1 violation, latest July 1, 2023 · highest 64.1667 UG/L
LE ROY3,498 peopleLE ROY, Illinois · 3 violations, latest July 1, 2025 · highest 0.073 MG/L (limit 0.06 MG/L)
MADILL3,410 peopleMarshall (county), Oklahoma · 15 violations, latest April 1, 2026 · highest 0.076 MG/L (limit 0.06 MG/L)
GROVELAND COMMUNITY SERV DIST3,400 peopleTuolumne (county), California · 2 violations, latest April 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
WEBB COUNTY WATER DISPENSER3,362 peopleWebb (county), Texas · 4 violations, latest July 1, 2025 · highest 0.075 MG/L (limit 0.06 MG/L)
MAYES CO RWD # 53,360 peopleMayes (county), Oklahoma · 1 violation, latest July 1, 2025 · highest 0.062 MG/L (limit 0.06 MG/L)
KEMMERER-DIAMONDVILLE JPB3,348 peopleKEMMERER, Wyoming · 2 violations, latest April 1, 2024 · highest 0.064 MG/L (limit 0.06 MG/L)
CLEVELAND MUNICIPAL AUTHORITY3,262 peoplePawnee (county), Oklahoma · 3 violations, latest April 1, 2025 · highest 0.076 MG/L (limit 0.06 MG/L)
Ely3,258 peopleSt. Louis (county), Minnesota · 3 violations, latest Oct. 1, 2024 · highest 0.0631 MG/L
GOFFSTOWN VILLAGE PCT3,250 peopleGOFFSTOWN, New Hampshire · 3 violations, latest Oct. 1, 2024 · highest 0.065 MG/L
STICKROSS MOUNTAIN WATER CO3,250 peopleCherokee (county), Oklahoma · 4 violations, latest April 1, 2026 · highest 0.081 MG/L (limit 0.06 MG/L)
LOUISIANA PWS3,244 peopleLOUISIANA, Missouri · 4 violations, latest Jan. 1, 2026 · highest 67.3 UG/L (limit 60 UG/L)
KOTZEBUE MUN. WATER SYSTEM3,234 peopleKOTZEBUE, Alaska · 10 violations, latest April 1, 2026 · highest 0.108 MG/L (limit 0.06 MG/L)
LYKENS BORO AUTH3,220 peopleDauphin (county), Pennsylvania · 2 violations, latest Oct. 1, 2024 · highest 0.066 MG/L
MOUNT IDA WATERWORKS3,218 peopleMontgomery (county), Arkansas · 5 violations, latest Oct. 1, 2025 · highest 94 UG/L (limit 80 UG/L)
FELLSMERE, CITY OF3,208 peopleFELLSMERE, Florida · 10 violations, latest Jan. 1, 2026 · highest 190.5 UG/L
SALMON CITY OF3,158 peopleLemhi (county), Idaho · 6 violations, latest April 1, 2026 · highest 0.102 MG/L (limit 0.06 MG/L)
EAST TAYLOR MUNI AUTH3,152 peopleCambria (county), Pennsylvania · 1 violation, latest Oct. 1, 2022 · highest 0.067 MG/L
CAL AM - BASS LAKE3,066 peopleMadera (county), California · 1 violation, latest April 1, 2026 · highest 0.065 MG/L (limit 0.06 MG/L)
ATOKA CO. RWS & SWMD #43,000 peopleAtoka (county), Oklahoma · 16 violations, latest Jan. 1, 2026 · highest 0.147 MG/L (limit 0.06 MG/L)
HEAVENER UTILITY AUTH - PSG3,000 peopleLe Flore (county), Oklahoma · 2 violations, latest July 1, 2025 · highest 0.063 MG/L (limit 0.06 MG/L)
ATOKA2,988 peopleAtoka (county), Oklahoma · 12 violations, latest April 1, 2026 · highest 0.078 MG/L (limit 0.06 MG/L)
SHAWNEE CO RWD 3C2,960 peopleTOPEKA, Kansas · 5 violations, latest April 1, 2025 · highest 0.073 MG/L (limit 0.06 MG/L)
HERITAGE RANCH CSD2,956 peopleSan Luis Obispo (county), California · 5 violations, latest Jan. 1, 2024 · highest 0.097 MG/L (limit 0.06 MG/L)
RINGGOLD2,953 peopleRINGGOLD, Georgia · 3 violations, latest Jan. 1, 2024 · highest 0.064 MG/L (limit 0.06 MG/L)
FLORIDA VILLAGE2,884 peopleFLORIDA (V), New York · 2 violations, latest July 1, 2018 · highest 65.5 UG/L (limit 60 UG/L)
TOWN OF GRAMERCY WATERWORKS2,860 peopleSt. James Parish (county), Louisiana · 4 violations, latest July 1, 2025 · highest 0.069 MG/L (limit 0.06 MG/L)
MAYSVILLE WATER SYSTEM2,838 peopleMAYSVILLE, Georgia · 4 violations, latest April 1, 2024 · highest 0.063 MG/L (limit 0.06 MG/L)
ST MARY PARISH WATER SEWERAGE COMM 12,823 peopleSt. Mary Parish (county), Louisiana · 2 violations, latest Oct. 1, 2025 · highest 0.069 MG/L (limit 0.06 MG/L)
CALERA PWA2,815 peopleBryan (county), Oklahoma · 18 violations, latest April 1, 2023 · highest 0.121 MG/L (limit 0.06 MG/L)
STROUD UTILITIES AUTHORITY2,811 peopleLincoln (county), Oklahoma · 10 violations, latest July 1, 2010 · highest 0.085 MG/L (limit 0.06 MG/L)
UPPER SURFACE CREEK DOMESTIC WUA2,800 peopleDelta (county), Colorado · 5 violations, latest July 1, 2023 · highest 0.069 MG/L (limit 0.06 MG/L)
WARRENTON2,800 peopleWARRENTON, Georgia · 6 violations, latest April 1, 2026 · highest 0.085 MG/L (limit 0.06 MG/L)
MCINTOSH CO. RWS & SWMD #2 (ONAPA)2,774 peopleMcIntosh (county), Oklahoma · 2 violations, latest Oct. 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
EUFAULA PWA2,766 peopleMcIntosh (county), Oklahoma · 20 violations, latest July 1, 2013 · highest 0.125 MG/L (limit 0.06 MG/L)
ROGERS CO RWD # 22,750 peopleRogers (county), Oklahoma · 2 violations, latest July 1, 2022 · highest 0.066 MG/L (limit 0.06 MG/L)
BISCOE, TOWN OF2,735 peopleBISCOE, North Carolina · 2 violations, latest July 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
TOWN OF EATONVILLE2,727 peopleEATONVILLE, Florida · 4 violations, latest April 1, 2022 · highest 74.03 UG/L
LAKELAND2,718 peopleLanier (county), Georgia · 4 violations, latest July 1, 2025 · highest 0.09 MG/L (limit 0.06 MG/L)
CITY OF JUNCTION2,700 peopleKimble (county), Texas · 3 violations, latest Jan. 1, 2025 · highest 0.069 MG/L (limit 0.06 MG/L)
CITY OF EAST TAWAKONI2,686 peopleRains (county), Texas · 3 violations, latest April 1, 2026 · highest 0.062 MG/L (limit 0.06 MG/L)
ALEXANDRIA WATER SYSTEM2,657 peopleDeKalb (county), Tennessee · 1 violation, latest April 1, 2022 · highest 0.0627 MG/L (limit 0.06 MG/L)
PENDLETON WATER ASSOCIATION2,634 peopleSabine Parish (county), Louisiana · 60 violations, latest April 1, 2025 · highest 175 UG/L (limit 60 UG/L)
HOMINY2,584 peopleOsage (county), Oklahoma · 21 violations, latest April 1, 2026 · highest 0.103 MG/L (limit 0.06 MG/L)
MUSKOGEE CO. RWD #62,550 peopleMuskogee (county), Oklahoma · 18 violations, latest Oct. 1, 2023 · highest 0.107 MG/L (limit 0.06 MG/L)
ANTLERS PWA2,547 peoplePushmataha (county), Oklahoma · 4 violations, latest April 1, 2024 · highest 0.063 MG/L (limit 0.06 MG/L)
REID VILLAGE WATER DISTRICT2,545 peopleMontgomery (county), Kentucky · 5 violations, latest July 1, 2023 · highest 0.082 MG/L (limit 0.06 MG/L)
CITY OF HUGHES SPRINGS2,527 peopleCass (county), Texas · 1 violation, latest July 1, 2023 · highest 0.064 MG/L (limit 0.06 MG/L)
NORTHWEST FLORIDA RECEPTION CENTER2,500 peopleCHIPLEY, Florida · 4 violations, latest July 1, 2024 · highest 89.825 UG/L
CONCORDIA PWS2,500 peopleCONCORDIA, Missouri · 1 violation, latest April 1, 2026 · highest 63.6 UG/L (limit 60 UG/L)
MONROE CITY PWS2,500 peopleMONROE CITY, Missouri · 4 violations, latest April 1, 2026 · highest 81 UG/L (limit 60 UG/L)
GRETNA, TOWN OF2,500 peoplePittsylvania (county), Virginia · 3 violations, latest Jan. 1, 2024 · highest 0.065 MG/L (limit 0.06 MG/L)
CREWE, TOWN OF2,465 peopleNottoway (county), Virginia · 4 violations, latest Jan. 1, 2026 · highest 0.101 MG/L (limit 0.06 MG/L)
LAKE HAMILTON, TOWN OF2,430 peopleLAKE HAMILTON, Florida · 1 violation, latest Jan. 1, 2026 · highest 69.475 UG/L
JOHNSONBURG MUNICIPAL AUTH2,413 peopleElk (county), Pennsylvania · 1 violation, latest Jan. 1, 2024 · highest 0.064 MG/L
TOMPKINSVILLE WATER WORKS2,404 peopleMonroe (county), Kentucky · 1 violation, latest April 1, 2026 · highest 0.063 MG/L (limit 0.06 MG/L)
LAGRANGE VILLAGE PWS2,400 peopleLorain (county), Ohio · 4 violations, latest Oct. 1, 2024 · highest 0.091 MG/L (limit 0.06 MG/L)
MAYES CO RWD # 32,400 peopleMayes (county), Oklahoma · 1 violation, latest July 1, 2025 · highest 0.062 MG/L (limit 0.06 MG/L)
PORTER PWA2,400 peopleWagoner (county), Oklahoma · 18 violations, latest Jan. 1, 2026 · highest 0.119 MG/L (limit 0.06 MG/L)
REYNOLDS WATER COMPANY2,370 peopleMercer (county), Pennsylvania · 4 violations, latest Oct. 1, 2025 · highest 0.157 MG/L
PINE HILL,TOWN OF2,361 peoplePINE HILL, Alabama · 2 violations, latest Jan. 1, 2026 · highest 0.062 MG/L (limit 0.06 MG/L)
FAIRVIEW UNION WATER SYSTEM2,346 peopleRed River Parish (county), Louisiana · 11 violations, latest April 1, 2026 · highest 0.144 MG/L (limit 0.06 MG/L)
SOUTHWEST ARKANSAS WATER SYSTEM2,335 peopleHempstead (county), Arkansas · 3 violations, latest April 1, 2025 · highest 72 UG/L (limit 60 UG/L)
MUSKOGEE CO. RWD #1 (OKTAHA)2,280 peopleMuskogee (county), Oklahoma · 4 violations, latest Jan. 1, 2025 · highest 0.067 MG/L (limit 0.06 MG/L)
CITY OF OVERTON2,275 peopleRusk (county), Texas · 1 violation, latest Jan. 1, 2024 · highest 0.062 MG/L (limit 0.06 MG/L)
EAST LOGAN CO RURAL WATER2,263 peopleLogan (county), Arkansas · 3 violations, latest July 1, 2024 · highest 68 UG/L (limit 60 UG/L)
NEODESHA, CITY OF2,246 peopleNEODESHA, Kansas · 1 violation, latest April 1, 2026 · highest 0.068 MG/L (limit 0.06 MG/L)
MCDOWELL COUNTY PSD BARTLEY2,242 peopleBARTLEY, ENGLISH, West Virginia · 2 violations, latest April 1, 2025 · highest 70 UG/L (limit 60 UG/L)
NACIMIENTO WATER COMPANY2,191 peopleSan Luis Obispo (county), California · 2 violations, latest Oct. 1, 2024 · highest 0.66 MG/L (limit 0.06 MG/L)
MINGO COUNTY PSD - NAUGATUCK2,159 peopleNAUGATUCK, West Virginia · 2 violations, latest July 1, 2025 · highest 70 UG/L (limit 60 UG/L)
ANDERSON CO RWD 1C2,112 peopleMOUND CITY, Kansas · 3 violations, latest April 1, 2025 · highest 0.068 MG/L (limit 0.06 MG/L)
CREEK CO RWD # 72,100 peopleCreek (county), Oklahoma · 6 violations, latest April 1, 2026 · highest 0.163 MG/L (limit 0.06 MG/L)
WAURIKA PUBLIC WORKS AUTHORITY2,100 peopleJefferson (county), Oklahoma · 8 violations, latest April 1, 2026 · highest 0.081 MG/L (limit 0.06 MG/L)
RONCEVERTE WATER2,091 peopleRONCEVERTE, West Virginia · 2 violations, latest Oct. 1, 2024 · highest 67 UG/L (limit 60 UG/L)
RUTHERFORD COLLEGE TOWN OF2,083 peopleRUTHERFORD COLL, North Carolina · 1 violation, latest July 1, 2024 · highest 0.066 MG/L (limit 0.06 MG/L)
MOUNTAIN TOP PSD2,072 peopleMT STORM, West Virginia · 2 violations, latest April 1, 2026 · highest 69 UG/L (limit 60 UG/L)
LAKE ST JOHN WATERWORKS DISTRICT 12,067 peopleConcordia Parish (county), Louisiana · 57 violations, latest July 1, 2023 · highest 122 UG/L (limit 60 UG/L)
PITTSBURG CO. RWD #7 (ARPELAR)2,040 peoplePittsburg (county), Oklahoma · 4 violations, latest Jan. 1, 2018 · highest 0.066 MG/L (limit 0.06 MG/L)
PHILMONT BOY SCOUT RANCH - HEADQUARTERS2,000 peopleColfax (county), New Mexico · 43 violations, latest Jan. 1, 2025 · highest 120.25 MG/L
WAGONER CO. RWD #22,000 peopleWagoner (county), Oklahoma · 1 violation, latest April 1, 2026 · highest 0.075 MG/L (limit 0.06 MG/L)
WESTERN CARTER CO WATER CORP2,000 peopleCarter (county), Oklahoma · 1 violation, latest Oct. 1, 2018 · highest 8.985 MG/L (limit 0.06 MG/L)
TOWN OF EDWARDS1,980 peopleHinds (county), Mississippi · 4 violations, latest Jan. 1, 2025 · highest 0.084 MG/L (limit 0.06 MG/L)
WEST WINN WATER SYSTEM, INC1,965 peopleWinn Parish (county), Louisiana · 11 violations, latest April 1, 2026 · highest 0.133 MG/L (limit 0.06 MG/L)
TANNEHILL WATER SYSTEM1,932 peopleWinn Parish (county), Louisiana · 12 violations, latest July 1, 2023 · highest 0.11 MG/L (limit 0.06 MG/L)
CITY OF HUXLEY1,930 peopleShelby (county), Texas · 11 violations, latest April 1, 2026 · highest 0.14 MG/L (limit 0.06 MG/L)
LAKESIDE WATER ASSOCIATION1,876 peopleColumbia (county), Arkansas · 4 violations, latest Oct. 1, 2019 · highest 74 UG/L (limit 60 UG/L)
ALBERTA WATER SYSTEM1,860 peopleBienville Parish (county), Louisiana · 1 violation, latest Oct. 1, 2024 · highest 0.062 MG/L (limit 0.06 MG/L)
SPIRO EAST WATER ASSOCIATION1,817 peopleLe Flore (county), Oklahoma · 8 violations, latest July 1, 2025 · highest 0.072 MG/L (limit 0.06 MG/L)
LIBERTY CORRECTIONAL INSTITUTION1,800 peopleBRISTOL, Florida · 1 violation, latest July 1, 2024 · highest 68.1 UG/L
MOUNT PLEASANT, TOWN OF1,786 peopleMT PLEASANT, North Carolina · 11 violations, latest April 1, 2026 · highest 0.118 MG/L (limit 0.06 MG/L)
HAMRICK PSD1,785 peopleHAMBLETON, HENDRICKS, ST. GEORGE, West Virginia · 3 violations, latest Jan. 1, 2025 · highest 67 UG/L (limit 60 UG/L)
OLD FARM HILL WATER DISTRICT1,768 peopleMOUNT PLEASANT (T), New York · 2 violations, latest Jan. 1, 2022 · highest 0.071 MG/L (limit 0.06 MG/L)
EBARB WWKS DIST #1 - NORTH EBARB1,761 peopleSabine Parish (county), Louisiana · 11 violations, latest April 1, 2026 · highest 0.083 MG/L (limit 0.06 MG/L)
PITTSBURG CO. RWD #51,750 peoplePittsburg (county), Oklahoma · 17 violations, latest Oct. 1, 2025 · highest 0.075 MG/L (limit 0.06 MG/L)
CWM WATER AUTHORITY1,749 peopleDICKINSON, Alabama · 6 violations, latest April 1, 2024 · highest 0.07 MG/L (limit 0.06 MG/L)
SLC WSC1,749 peopleLimestone (county), Texas · 3 violations, latest Oct. 1, 2024 · highest 0.081 MG/L (limit 0.06 MG/L)
SUGARLOAF WATER ASSOCIATION1,730 peopleCARRABASSETT VL, Maine · 4 violations, latest April 1, 2024 · highest 0.143 MG/L (limit 0.06 MG/L)
ST ROSE PWD1,688 peopleClinton (county), Illinois · 1 violation, latest Jan. 1, 2025 · highest 0.065 MG/L (limit 0.06 MG/L)
BEAVER MEADOW WATERWORKS ASSOCIATION1,687 peopleJasper (county), Mississippi · 1 violation, latest April 1, 2022 · highest 0.076 MG/L (limit 0.06 MG/L)
PITTSBURG CO. RWD #141,680 peoplePittsburg (county), Oklahoma · 12 violations, latest Jan. 1, 2026 · highest 0.087 MG/L (limit 0.06 MG/L)
SAXTON MUNI WATER AUTH1,675 peopleBedford (county), Pennsylvania · 1 violation, latest April 1, 2024 · highest 0.071 MG/L
BLACKLICK VALLEY MUNI AUTH1,650 peopleCambria (county), Pennsylvania · 3 violations, latest April 1, 2026 · highest 0.063 MG/L
CONTOOCOOK VILLAGE PCT1,600 peopleHOPKINTON, New Hampshire · 10 violations, latest April 1, 2026 · highest 0.16 MG/L
ROBBINS WATER SYSTEM1,579 peopleROBBINS, North Carolina · 4 violations, latest July 1, 2025 · highest 0.077 MG/L (limit 0.06 MG/L)
METLAKATLA1,575 peopleMETLAKATLA, Alaska · 4 violations, latest July 1, 2023 · highest 0.133 MG/L (limit 0.06 MG/L)
FAIRFAX1,555 peopleOsage (county), Oklahoma · 5 violations, latest April 1, 2020 · highest 0.092 MG/L (limit 0.06 MG/L)
LOUISA, TOWN OF1,555 peopleLouisa (county), Virginia · 3 violations, latest Jan. 1, 2026 · highest 72 UG/L (limit 60 UG/L)
HICO WATER SYSTEM1,530 peopleLincoln Parish (county), Louisiana · 3 violations, latest April 1, 2024 · highest 0.089 MG/L (limit 0.06 MG/L)
NORTHWESTERN W AND SD - MCCOMB1,527 peopleHancock (county), Ohio · 7 violations, latest Jan. 1, 2024 · highest 0.086 MG/L (limit 0.06 MG/L)
CAMP INN ASSOCIATES, LLC1,500 peopleFROSTPROOF, Florida · 2 violations, latest Jan. 1, 2024 · highest 64.92 UG/L
LATIMER CO. RWD #21,500 peopleLatimer (county), Oklahoma · 1 violation, latest April 1, 2026 · highest 0.065 MG/L (limit 0.06 MG/L)
COLTON WATER DISTRICT1,500 peopleClackamas (county), Oregon · 1 violation, latest Jan. 1, 2024 · highest 0.0807 MG/L (limit 0.06 MG/L)
CHEROKEE CO. RWD #2 (KEYS)1,493 peopleCherokee (county), Oklahoma · 1 violation, latest Jan. 1, 2023 · highest 0.073 MG/L (limit 0.06 MG/L)
CENTERTOWN WATER SYSTEM1,485 peopleOhio (county), Kentucky · 1 violation, latest July 1, 2025 · highest 0.066 MG/L (limit 0.06 MG/L)
MOUNT GILEAD, TOWN OF1,463 peopleMT GILEAD, North Carolina · 2 violations, latest Jan. 1, 2025 · highest 0.064 MG/L (limit 0.06 MG/L)
MO AMERICAN IRONTON1,460 peopleIRONTON, Missouri · 1 violation, latest Jan. 1, 2024 · highest 61.45 UG/L (limit 60 UG/L)
SPICEWOOD BEACH1,452 peopleBurnet (county), Texas · 1 violation, latest Jan. 1, 2024 · highest 0.066 MG/L (limit 0.06 MG/L)
WETUMKA1,451 peopleHughes (county), Oklahoma · 10 violations, latest Jan. 1, 2026 · highest 0.083 MG/L (limit 0.06 MG/L)
FOOD PROCESSORS WATER COOPERATIVE, INC1,430 peopleRockingham (county), Virginia · 1 violation, latest July 1, 2024 · highest 63 UG/L (limit 60 UG/L)
AFTON PWA1,428 peopleOttawa (county), Oklahoma · 1 violation, latest July 1, 2013 · highest 0.065 MG/L (limit 0.06 MG/L)
LINN COUNTY CONS PWSD 11,420 peoplePURDIN, Missouri · 1 violation, latest April 1, 2026 · highest 62.9 UG/L (limit 60 UG/L)
RALEIGH COUNTY PSD CLEAR CREEK1,407 peopleCLEAR CREEK, West Virginia · 1 violation, latest Oct. 1, 2024 · highest 70 UG/L (limit 60 UG/L)
RAINELLE WATER DEPT1,381 peopleRAINELLE, West Virginia · 6 violations, latest Oct. 1, 2024 · highest 95 UG/L (limit 60 UG/L)
LOOKOUT MOUNTAIN WD1,378 peopleClear Creek (county), Colorado · 2 violations, latest Oct. 1, 2023 · highest 0.06265 MG/L (limit 0.06 MG/L)
BEGGS PUBLIC WORKS AUTHORITY1,364 peopleOkmulgee (county), Oklahoma · 12 violations, latest Oct. 1, 2025 · highest 0.098 MG/L (limit 0.06 MG/L)

The 300 systems serving the most people are listed here; every one of the 613 is on its state's page (the states above).

From EPA's Safe Drinking Water Information System (SDWIS), through EPA ECHO's drinking water system download. Health-based violations from EPA Envirofacts, downloaded Nov. 2, 2026. EPA's file dated Oct. 23, 2026. EPA: “All compliance and enforcement data displayed on ECHO are current as of the last official quarterly refresh of the source data system, SDWIS, which may lag by three to six months.” These are records of violations, not a test of your tap water today: your water system's annual Consumer Confidence Report has its test results. Names and values are shown as EPA writes them. EPA ECHO drinking water search.