U.S. safety records, as the agencies wrote them. Independent.
Tap water · contaminant or rule

Combined Uranium in drinking water

The community water systems with a health-based violation of Combined Uranium on EPA's record since Oct. 23, 2023, most people served first. EPA's file dated Oct. 23, 2026.

88

88 systems serving 116,997 people in 20 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

California 28Texas 8New Hampshire 6North Carolina 6Nebraska 5Idaho 5Oklahoma 5New Mexico 4Arizona 4Kansas 3Colorado 3Wyoming 2Nevada 2Montana 1Georgia 1Florida 1Washington 1Alaska 1Maine 1Vermont 1

Systems

  • GRAND ISLAND, CITY OF51,478 peopleGRAND ISLAND, Nebraska · 2 violations, latest Oct. 1, 2025 · highest 32 UG/L (limit 30 UG/L)
  • DONA ANA MDWCA16,987 peopleDONA ANA, New Mexico · 3 violations, latest April 1, 2026 · highest 48 UG/L (limit 30 UG/L)
  • CAPITOL WATER CORP9,000 peopleAda (county), Idaho · 2 violations, latest April 1, 2025 · highest 31 UG/L (limit 30 UG/L)
  • WHEATLAND, TOWN OF3,659 peopleWHEATLAND, Wyoming · 1 violation, latest Jan. 1, 2026 · highest 31.1 UG/L (limit 30 UG/L)
  • GREEN VALLEY MWC2,993 peopleSan Bernardino (county), California · 1 violation, latest Oct. 1, 2024 · highest 23.25 PCI/L (limit 20 PCI/L)
  • PINE VALLEY MUTUAL WC2,574 peopleSan Diego (county), California · 8 violations, latest July 1, 2025 · highest 24.4 PCI/L (limit 20 PCI/L)
  • JIM WELLS COUNTY FWSD 11,950 peopleJim Wells (county), Texas · 8 violations, latest Jan. 1, 2026 · highest 52 UG/L (limit 30 UG/L)
  • APACHE1,521 peopleCaddo (county), Oklahoma · 1 violation, latest July 1, 2022 · highest 31 UG/L (limit 30 UG/L)
  • WHITEHALL TOWN OF1,500 peopleWHITEHALL, Montana · 10 violations, latest Jan. 1, 2026 · highest 0.0449 MG/L (limit 0.03 MG/L)
  • LEBEC COUNTY WATER DISTRICT1,379 peopleKern (county), California · 3 violations, latest July 1, 2025 · highest 25 PCI/L
  • ENFIELD WATER DEPT1,345 peopleENFIELD, New Hampshire · 4 violations, latest Oct. 1, 2025 · highest 34 UG/L
  • DEL ORO RIVER ISLAND SERV TERR #11,277 peopleTulare (county), California · 9 violations, latest Oct. 1, 2025 · highest 49.5 PCI/L (limit 20 PCI/L)
  • VILLAGE DISTRICT OF EIDELWEISS1,200 peopleMADISON, New Hampshire · 7 violations, latest July 1, 2025 · highest 67 UG/L
  • ROCKBRIDGE S/D1,042 peopleKNIGHTDALE, North Carolina · 4 violations, latest July 1, 2026 · highest 74.2 PCI/L (limit 20.1 PCI/L)
  • LEXINGTON1,015 peopleLEXINGTON, Georgia · 10 violations, latest April 1, 2026 · highest 112 UG/L (limit 30 UG/L)
  • RIVIERA WCID936 peopleKleberg (county), Texas · 11 violations, latest Jan. 1, 2026 · highest 103 UG/L (limit 30 UG/L)
  • DESCANSO COMMUNITY WATER DISTRICT870 peopleSan Diego (county), California · 9 violations, latest Oct. 1, 2025 · highest 25.5 PCI/L (limit 20 PCI/L)
  • Nambe Pueblo800 peopleNew Mexico · 2 violations, latest July 1, 2024 · highest 38 UG/L
  • DAGGETT COMM SVCS DIST795 peopleSan Bernardino (county), California · 11 violations, latest April 1, 2026 · highest 39 PCI/L (limit 20 PCI/L)
  • AMBER ACRES NORTH S/D752 peopleKNIGHTDALE, North Carolina · 4 violations, latest July 1, 2023 · highest 28.6 PCI/L (limit 20.1 PCI/L)
  • DEERFIELD, CITY OF692 peopleDEERFIELD, Kansas · 2 violations, latest Jan. 1, 2024 · highest 31 UG/L (limit 30 UG/L)
  • CS TIERRA MESA ESTATES WATER COMPANY632 peopleYUMA, Arizona · 9 violations, latest April 1, 2026 · highest 44 UG/L (limit 30 UG/L)
  • TRADEWIND WATER ASSOC.632 peopleKern (county), California · 10 violations, latest April 1, 2025 · highest 24 PCI/L
  • CSA 70 W-3 HACIENDA611 peopleSan Bernardino (county), California · 11 violations, latest April 1, 2026 · highest 29.5 PCI/L (limit 20 PCI/L)
  • ASHLEY HILLS NORTH S/D602 peopleKNIGHTDALE, North Carolina · 3 violations, latest July 1, 2026 · highest 62.5 PCI/L (limit 20.1 PCI/L)
  • RIVERVIEW MOBILE HOME ESTATES540 peopleStanislaus (county), California · 6 violations, latest Jan. 1, 2026 · highest 23 PCI/L (limit 20 PCI/L)
  • KNOLL ENTERPRISES500 peopleSan Bernardino (county), California · 8 violations, latest April 1, 2026 · highest 24 PCI/L (limit 20 PCI/L)
  • MANZANOLA TOWN OF497 peopleOtero (county), Colorado · 7 violations, latest July 1, 2026 · highest 48 UG/L (limit 30 UG/L)
  • SOUTHERN TRACE S/D485 peopleGARNER, North Carolina · 2 violations, latest July 1, 2026 · highest 25.3 PCI/L (limit 20.1 PCI/L)
  • RIDGEHAVEN S/D455 peopleKNIGHTDALE, North Carolina · 2 violations, latest Oct. 1, 2024 · highest 23.8 PCI/L (limit 20.1 PCI/L)
  • Big Sandy Rancheria408 peopleBig Sandy Rancheria, California · 4 violations, latest Jan. 1, 2025 · highest 0.13533 MG/L
  • OAK PARK MOBILE HOME VILLAGE400 peopleALVA, Florida · 2 violations, latest July 1, 2025 · highest 86.3 PCI/L
  • SANTA CRUZ WATER ASSOCIATION394 peopleSANTA CRUZ, New Mexico · 11 violations, latest April 1, 2026 · highest 36 UG/L (limit 30 UG/L)
  • PHILLIPS, VILLAGE OF385 peoplePHILLIPS, Nebraska · 22 violations, latest April 1, 2026 · highest 42 UG/L (limit 30 UG/L)
  • RIO BRAZOS WATER SYSTEM360 peopleKent (county), Texas · 6 violations, latest Jan. 1, 2026 · highest 85 UG/L (limit 30 UG/L)
  • COOK, VILLAGE OF335 peopleCOOK, Nebraska · 1 violation, latest July 1, 2025 · highest 40 UG/L (limit 30 UG/L)
  • ELK POINT COUNTRY CLUB325 peopleDouglas (county), Nevada · 3 violations, latest July 1, 2023 · highest 0.032 MG/L (limit 0.03 MG/L)
  • CSA 70-F MORONGO300 peopleSan Bernardino (county), California · 11 violations, latest April 1, 2026 · highest 50.8 PCI/L (limit 20 PCI/L)
  • PAGELS TP300 peopleMorgan (county), Colorado · 9 violations, latest Jan. 1, 2024 · highest 51.25 UG/L (limit 30 UG/L)
  • MISSION CREEK WATER ASSN263 peopleBoundary (county), Idaho · 26 violations, latest April 1, 2026 · highest 74 UG/L (limit 30 UG/L)
  • OAKVALE PARK260 peopleSan Diego (county), California · 1 violation, latest Jan. 1, 2024 · highest 38.4 PCI/L (limit 20 PCI/L)
  • RAINBIRD VALLEY MWC238 peopleKern (county), California · 9 violations, latest Oct. 1, 2025 · highest 52 PCI/L
  • TOWN NORTH ESTATES216 peopleLubbock (county), Texas · 7 violations, latest Oct. 1, 2025 · highest 40 UG/L (limit 30 UG/L)
  • MD 07 MARINA VIEW HEIGHTS200 peopleMadera (county), California · 14 violations, latest Jan. 1, 2014 · highest 279 PCI/L (limit 20 PCI/L)
  • SIERRA LINDA MUTUAL WATER CO200 peopleMadera (county), California · 10 violations, latest April 1, 2026 · highest 423.33 PCI/L (limit 20 PCI/L)
  • FCWWD 40 - SHAVER SPRINGS196 peopleFresno (county), California · 1 violation, latest April 1, 2026 · highest 96.4 PCI/L (limit 20 PCI/L)
  • LAKESIDE PARK180 peopleFerry (county), Washington · 5 violations, latest April 1, 2026 · highest 31.5 UG/L
  • WALES WATER SYSTEM173 peopleWALES, Alaska · 2 violations, latest July 1, 2025 · highest 40 UG/L (limit 30 UG/L)
  • FREEDOM VILLAGE CONDOS165 peopleFREEDOM, New Hampshire · 2 violations, latest Oct. 1, 2025 · highest 82 UG/L
  • SPRING MEADOW MOBILE HOME PARK163 peopleMidland (county), Texas · 2 violations, latest Oct. 1, 2025 · highest 35 UG/L (limit 30 UG/L)
  • CREEKSIDE SOUTH ESTATES METRO DISTRICT160 peopleAdams (county), Colorado · 2 violations, latest Jan. 1, 2026 · highest 46 UG/L (limit 30 UG/L)
  • POJOAQUE TERRACES MHP160 peoplePOJOAQUE, New Mexico · 11 violations, latest April 1, 2026 · highest 79 UG/L (limit 30 UG/L)
  • RUSH CENTER, CITY OF144 peopleRUSH CENTER, Kansas · 9 violations, latest Oct. 1, 2025 · highest 61 UG/L (limit 30 UG/L)
  • SUN LEISURE ESTATES IMPROVEMENT DISTRICT143 peopleYUMA, Arizona · 3 violations, latest April 1, 2026 · highest 47 UG/L (limit 30 UG/L)
  • OLD RIVER MUTUAL WATER COMPANY130 peopleKern (county), California · 5 violations, latest Oct. 1, 2025 · highest 28 PCI/L
  • CS RANCHEROS BONITOS WATER COMPANY120 peopleYUMA, Arizona · 9 violations, latest April 1, 2026 · highest 37 UG/L (limit 30 UG/L)
  • SMILEY CREEK WATER USERS ASSN INC117 peopleBlaine (county), Idaho · 1 violation, latest Jan. 1, 2024 · highest 543 UG/L (limit 30 UG/L)
  • GUATAY MUTUAL BENEFIT CORPORATION100 peopleSan Diego (county), California · 2 violations, latest Oct. 1, 2023 · highest 71 PCI/L (limit 20 PCI/L)
  • MD 42 STILL MEADOW100 peopleMadera (county), California · 5 violations, latest Oct. 31, 2024 · highest 57.5 PCI/L (limit 20 PCI/L)
  • WILLOWSIDE TERRACE WATER ASSOCIATION100 peopleSan Diego (county), California · 3 violations, latest March 1, 2024 · highest 115 PCI/L (limit 20 PCI/L)
  • IDAHO YOUTH RANCH HANDS OF PROMISE95 peopleCanyon (county), Idaho · 6 violations, latest Jan. 1, 2023 · highest 32 UG/L (limit 30 UG/L)
  • COTTONWOOD ACRES95 peopleTORRINGTON, Wyoming · 7 violations, latest Jan. 1, 2026 · highest 39.5 UG/L (limit 30 UG/L)
  • BROOKSVILLE90 peoplePottawatomie (county), Oklahoma · 8 violations, latest Jan. 1, 2025 · highest 40 UG/L (limit 30 UG/L)
  • WHIPPOORWILL HILL MOBILE HOME85 peopleWISCASSET, Maine · 3 violations, latest Jan. 1, 2026 · highest 0.034 MG/L (limit 0.03 MG/L)
  • MEADOW GLEN S/D84 peopleKNIGHTDALE, North Carolina · 6 violations, latest Jan. 1, 2024 · highest 34.8 PCI/L (limit 20.1 PCI/L)
  • SIMPSON, CITY OF81 peopleSIMPSON, Kansas · 1 violation, latest Oct. 1, 2025 · highest 38 UG/L (limit 30 UG/L)
  • MARTINSBURG, VILLAGE OF78 peoplePONCA, Nebraska · 35 violations, latest Oct. 1, 2023 · highest 43 UG/L (limit 30 UG/L)
  • FRANKLIN DOMESTIC WATER USERS75 peopleAda (county), Idaho · 4 violations, latest Oct. 1, 2023 · highest 16698 UG/L (limit 30 UG/L)
  • VALLEY ESTATES68 peopleLubbock (county), Texas · 9 violations, latest Jan. 1, 2026 · highest 60 UG/L (limit 30 UG/L)
  • MARTIN'S MOBILE HOME COURT60 peopleStanislaus (county), California · 8 violations, latest Jan. 1, 2026 · highest 69 PCI/L (limit 30 PCI/L)
  • MARGIES MHP60 peopleMidland (county), Texas · 7 violations, latest Oct. 1, 2025 · highest 60 UG/L (limit 30 UG/L)
  • THE DOX CONDOS55 peopleSANDOWN, New Hampshire · 3 violations, latest July 1, 2024 · highest 40 UG/L
  • ROSEMOUNT WATER CO54 peopleWashoe (county), Nevada · 59 violations, latest April 1, 2026 · highest 65 UG/L (limit 30 UG/L)
  • COUNTRY VIEW MHP54 peopleLubbock (county), Texas · 10 violations, latest Jan. 1, 2026 · highest 130 UG/L (limit 30 UG/L)
  • EAGLES NEST ESTATES52 peopleCHADRON, Nebraska · 9 violations, latest Oct. 1, 2025 · highest 63 UG/L (limit 30 UG/L)
  • NEWBURY ELDERLY HOUSING51 peopleNEWBURY, New Hampshire · 1 violation, latest April 1, 2025 · highest 34 UG/L
  • VERNON HALL50 peopleVERNON, Vermont · 5 violations, latest Jan. 1, 2024 · highest 178 UG/L (limit 20 UG/L)
  • RED WAGON MHP46 peoplePayne (county), Oklahoma · 1 violation, latest Oct. 1, 2025 · highest 33 UG/L (limit 30 UG/L)
  • BASS LAKE ANNEX 342 peopleMadera (county), California · 4 violations, latest July 1, 2025 · highest 38.8 PCI/L (limit 20 PCI/L)
  • INDIAN HILLS CAMP36 peopleSan Diego (county), California · 9 violations, latest Jan. 1, 2026 · highest 160 PCI/L (limit 20 PCI/L)
  • R.S. MUTUAL WATER COMPANY35 peopleKern (county), California · 6 violations, latest Oct. 1, 2025 · highest 29 PCI/L
  • TWO TWENTY FOUR MOBILE HOME PK35 peopleMadera (county), California · 31 violations, latest Oct. 1, 2025 · highest 350 PCI/L (limit 20 PCI/L)
  • SOUTH KERN MUTUAL WATER COMPANY32 peopleKern (county), California · 5 violations, latest Oct. 1, 2025 · highest 26 PCI/L
  • EASTSIDE MHP32 peopleGrady (county), Oklahoma · 2 violations, latest Jan. 1, 2024 · highest 35 PCI/L
  • CS CARTER WATER COMPANY28 peopleCARTER, Arizona · 3 violations, latest April 1, 2026 · highest 69 UG/L (limit 30 UG/L)
  • CORNERSTONE PLACE25 peopleDEERFIELD, New Hampshire · 1 violation, latest July 1, 2025 · highest 49 UG/L
  • SHADY OAKS MOBILE HOME PARK LLC23 peopleMadera (county), California · 10 violations, latest Jan. 1, 2026 · highest 592.5 PCI/L (limit 20 PCI/L)
  • PECAN TREE WATER ASSN22 peopleCleveland (county), Oklahoma · 14 violations, latest April 1, 2025 · highest 45 UG/L (limit 30 UG/L)

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.