Water Systems with Most Unresolved Health-Based Violations — 2026
U.S. community water systems ranked by the number of unresolved federal health-based drinking water violations in EPA's SDWIS enforcement records. Published alongside demographic context from the Census American Community Survey.
ranked
with demographic data
vintage
boundaries (March 2026)
Out of 5,893 medium and large community water systems with sufficient data, these 100 utilities have the most health-based violation records not marked resolved in EPA's enforcement data. The list is sorted by that count; demographic context from the U.S. Census is shown in neighboring columns, but is not a ranking input.
| Rank | Water System | State | Pop served | Unresolved health violations | Health viol. (since 2021) | % PoC served | % Below 200% FPL | Last violation |
|---|---|---|---|---|---|---|---|---|
| 1 | Herkimer Village | New York | 3,517 | 19 | 20 | 10% | 33% | 2026-01-01 |
| 2 | City of Bogalusa Water System | Louisiana | 7,294 | 11 | 12 | 43% | 49% | 2025-07-01 |
| 3 | Tallulah Water System | Louisiana | 5,558 | 9 | 25 | 71% | 62% | 2026-01-01 |
| 4 | Grambling Water System | Louisiana | 3,903 | 9 | 11 | 73% | 69% | 2025-11-18 |
| 5 | Rayville Water System | Louisiana | 3,326 | 9 | 9 | 40% | 49% | 2025-10-01 |
| 6 | Belen Water System | New Mexico | 6,293 | 8 | 24 | 69% | 45% | 2025-12-21 |
| 7 | Gallup Water System | New Mexico | 19,516 | 8 | 8 | 85% | 52% | 2026-01-01 |
| 8 | City of Pineville Water System | Louisiana | 12,621 | 7 | 16 | 28% | 32% | 2026-01-30 |
| 9 | Town of Haughton Water System | Louisiana | 3,872 | 7 | 8 | 25% | 41% | 2025-08-16 |
| 10 | Aiken City of (0210001) | South Carolina | 42,344 | 7 | 7 | 37% | 31% | 2021-07-01 |
| 11 | City of Winnfield Water System | Louisiana | 3,924 | 6 | 8 | 47% | 47% | 2026-02-04 |
| 12 | Calcasieu Parish Ww District No 4 | Louisiana | 3,620 | 6 | 7 | 18% | 35% | 2025-10-28 |
| 13 | Marion Waterworks | Arkansas | 9,027 | 6 | 6 | 50% | 32% | 2025-12-01 |
| 14 | Village Water System | Louisiana | 7,222 | 5 | 19 | 29% | 43% | 2024-07-01 |
| 15 | Winnsboro Water System | Louisiana | 4,426 | 5 | 11 | 39% | 52% | 2026-03-18 |
| 16 | Truth Or Consequences | New Mexico | 6,039 | 3 | 17 | 41% | 57% | 2025-11-30 |
| 17 | City of Leesville Water System | Louisiana | 5,774 | 3 | 4 | 28% | 42% | 2024-01-01 |
| 18 | Camino Real Regional Utility Authority | New Mexico | 9,903 | 2 | 29 | 95% | 61% | 2025-11-10 |
| 19 | Tri Cnty Jt Muni Auth | Pennsylvania | 3,692 | 2 | 12 | 10% | 31% | 2025-10-20 |
| 20 | Nueces County Wcid 3 | Texas | 7,192 | 2 | 8 | 76% | 40% | 2026-04-13 |
| 21 | City of La Joya | Texas | 4,221 | 2 | 8 | 97% | 53% | 2026-04-02 |
| 22 | Bluewell Public Service District | West Virginia | 4,181 | 2 | 5 | 15% | 44% | 2026-02-13 |
| 23 | Mountain Lakes Water Company | Virginia | 4,905 | 2 | 4 | 23% | 24% | 2025-05-04 |
| 24 | Wheeling Water | West Virginia | 22,623 | 2 | 3 | 10% | 34% | 2025-08-01 |
| 25 | Roswell Municipal Water System | New Mexico | 45,612 | 2 | 2 | 63% | 47% | 2025-08-16 |
| 26 | City of Jennings Water System | Louisiana | 9,789 | 2 | 2 | 24% | 36% | 2024-01-01 |
| 27 | Lawrenceville | Illinois | 3,929 | 2 | 2 | 13% | 31% | 2026-01-01 |
| 28 | Mitchell Water Department | Indiana | 3,832 | 2 | 2 | 7% | 35% | 2025-10-07 |
| 29 | Franklin Water Supply | Louisiana | 8,444 | 1 | 31 | 55% | 45% | 2025-06-21 |
| 30 | City of Big Spring | Texas | 22,935 | 1 | 21 | 55% | 31% | 2026-04-01 |
| 31 | City of Hughson | California | 6,241 | 1 | 20 | 44% | 23% | 2025-07-01 |
| 32 | Multi-County Water Supply Corporation | Texas | 3,441 | 1 | 19 | 25% | 33% | 2026-04-01 |
| 33 | City of Port Lavaca | Texas | 9,899 | 1 | 17 | 64% | 32% | 2026-05-04 |
| 34 | Rogers Company RWD # 3 Lake Plant | Oklahoma | 24,464 | 1 | 16 | 30% | 25% | 2025-07-01 |
| 35 | Hudson Water Supply Corporation | Texas | 7,764 | 1 | 16 | 41% | 38% | 2026-04-01 |
| 36 | City of Marlin | Texas | 4,758 | 1 | 15 | 70% | 57% | 2026-04-01 |
| 37 | City of Gladewater | Texas | 3,621 | 1 | 15 | 28% | 35% | 2026-03-10 |
| 38 | Chickasha Municipal Authority | Oklahoma | 14,635 | 1 | 13 | 26% | 38% | 2024-10-17 |
| 39 | Gbra Calhoun County Rural Water System | Texas | 4,431 | 1 | 12 | 64% | 32% | 2026-05-04 |
| 40 | Suisun-Solano Water Authority | California | 28,675 | 1 | 11 | 78% | 24% | 2024-10-17 |
| 41 | Mingo County Public Service District - Naugatuck | West Virginia | 4,110 | 1 | 11 | 5% | 51% | 2026-02-25 |
| 42 | Syracuse City | New York | 136,521 | 1 | 10 | 50% | 53% | 2026-03-30 |
| 43 | Yosemite Spring Park Util Company | California | 3,941 | 1 | 9 | 27% | 22% | 2025-10-06 |
| 44 | City of Avenal | California | 4,483 | 1 | 6 | 92% | 58% | 2024-10-17 |
| 45 | Antigo Waterworks | Wisconsin | 7,679 | 1 | 5 | 7% | 35% | 2025-07-02 |
| 46 | Town of Church Point Water System | Louisiana | 3,655 | 1 | 5 | 27% | 39% | 2025-02-01 |
| 47 | Bayou Teche Water Works | Louisiana | 3,454 | 1 | 5 | 29% | 38% | 2025-07-01 |
| 48 | Dewey Public Works Authority | Oklahoma | 7,526 | 1 | 4 | 30% | 44% | 2024-10-17 |
| 49 | City of Hitchcock | Texas | 6,490 | 1 | 4 | 51% | 32% | 2026-04-01 |
| 50 | Westlake City of Water System | Louisiana | 5,281 | 1 | 4 | 18% | 36% | 2024-12-18 |
| 51 | Cross Roads Special Utility District | Texas | 3,414 | 1 | 4 | 41% | 35% | 2026-04-02 |
| 52 | Yucaipa Valley Water District | California | 60,758 | 1 | 3 | 45% | 25% | 2026-03-17 |
| 53 | East Niles Csd | California | 31,094 | 1 | 3 | 78% | 45% | 2024-10-17 |
| 54 | Belleville Water Department | New Jersey | 27,993 | 1 | 3 | 70% | 21% | 2026-03-11 |
| 55 | City of San Luis | Arizona | 23,211 | 1 | 3 | 97% | 53% | 2024-10-01 |
| 56 | City of Groves | Texas | 16,855 | 1 | 3 | 47% | 31% | 2026-04-02 |
| 57 | Sparta Twp Water Utility - Lake Mohawk | New Jersey | 10,607 | 1 | 3 | 17% | 7% | 2025-07-01 |
| 58 | Roxbury Twp W Department-Sky V | New Jersey | 4,315 | 1 | 3 | 32% | 11% | 2026-01-01 |
| 59 | Dan River Water Inc. | North Carolina | 4,147 | 1 | 3 | 32% | 39% | 2026-01-01 |
| 60 | Falfurrias Utility Board | Texas | 3,927 | 1 | 3 | 92% | 50% | 2026-03-05 |
| 61 | Greater Harrison Public Service District Valley of Good Hope | West Virginia | 3,707 | 1 | 3 | 6% | 32% | 2025-10-01 |
| 62 | Oakdale Estates and Lake Suente | Mississippi | 3,328 | 1 | 3 | 41% | 40% | 2025-01-01 |
| 63 | Epcor - Agua Fria | Arizona | 108,742 | 1 | 2 | 35% | 18% | 2025-08-24 |
| 64 | Medford Water Department (Mwra) | Massachusetts | 53,847 | 1 | 2 | 35% | 20% | 2023-11-01 |
| 65 | Andover Water Department | Massachusetts | 35,936 | 1 | 2 | 30% | 9% | 2022-01-01 |
| 66 | Steubenville, City of | Ohio | 16,499 | 1 | 2 | 21% | 39% | 2025-04-03 |
| 67 | Versailles Water System | Kentucky | 13,174 | 1 | 2 | 15% | 26% | 2024-10-17 |
| 68 | City of Henderson | Texas | 10,814 | 1 | 2 | 42% | 32% | 2026-04-01 |
| 69 | City of Breaux Bridge Water System | Louisiana | 9,417 | 1 | 2 | 38% | 41% | 2021-07-08 |
| 70 | Sequoyah Co. RWD #8 | Oklahoma | 8,040 | 1 | 2 | 40% | 46% | 2025-04-01 |
| 71 | Logan County Psd - Northern Regional | West Virginia | 7,516 | 1 | 2 | 5% | 47% | 2026-03-25 |
| 72 | Albion | Michigan | 7,221 | 1 | 2 | 31% | 47% | 2026-01-01 |
| 73 | City of Ville Platte Water System | Louisiana | 6,922 | 1 | 2 | 39% | 49% | 2026-03-30 |
| 74 | Page City of | Arizona | 6,887 | 1 | 2 | 67% | 36% | 2023-08-01 |
| 75 | Rogers Company RWD # 4 | Oklahoma | 6,807 | 1 | 2 | 29% | 27% | 2024-10-17 |
| 76 | Arizona Water Company - Bisbee | Arizona | 5,551 | 1 | 2 | 37% | 45% | 2024-10-17 |
| 77 | City of Covington | Virginia | 5,291 | 1 | 2 | 12% | 35% | 2026-03-01 |
| 78 | Osceola Waterworks | Arkansas | 4,626 | 1 | 2 | 64% | 45% | 2026-04-30 |
| 79 | Sparta | Illinois | 3,808 | 1 | 2 | 18% | 34% | 2025-10-01 |
| 80 | Mcwa | New York | 379,635 | 1 | 1 | 22% | 21% | 2025-01-01 |
| 81 | Rochester City | New York | 207,181 | 1 | 1 | 60% | 46% | 2025-01-01 |
| 82 | Scwa - Laguna/Vineyard | California | 145,429 | 1 | 1 | 69% | 19% | 2024-10-17 |
| 83 | City of Georgetown | Texas | 108,823 | 1 | 1 | 32% | 16% | 2026-04-01 |
| 84 | City of Fairfield | California | 101,593 | 1 | 1 | 72% | 25% | 2024-10-17 |
| 85 | Rio Rancho Water & Ww Services | New Mexico | 81,230 | 1 | 1 | 54% | 22% | 2026-03-23 |
| 86 | Dearborn Heights | Michigan | 54,839 | 1 | 1 | 19% | 40% | 2025-01-09 |
| 87 | City of Porterville | California | 48,713 | 1 | 1 | 79% | 49% | 2024-10-17 |
| 88 | City of Los Banos | California | 43,989 | 1 | 1 | 80% | 39% | 2024-10-17 |
| 89 | City of Ceres | California | 36,788 | 1 | 1 | 78% | 39% | 2024-10-17 |
| 90 | City of Calexico | California | 36,151 | 1 | 1 | 98% | 49% | 2024-10-17 |
| 91 | Monterey Park-City, Water Department | California | 34,690 | 1 | 1 | 94% | 35% | 2024-10-17 |
| 92 | City of Weslaco | Texas | 34,317 | 1 | 1 | 90% | 53% | 2026-04-02 |
| 93 | Covington Water Supply | Louisiana | 26,739 | 1 | 1 | 21% | 23% | 2025-03-11 |
| 94 | Central Stickney Sd | Illinois | 24,532 | 1 | 1 | 55% | 25% | 2025-08-22 |
| 95 | City of Sanger | California | 24,321 | 1 | 1 | 75% | 34% | 2024-10-17 |
| 96 | Cedar City Waterworks | Utah | 24,268 | 1 | 1 | 17% | 37% | 2025-03-05 |
| 97 | San Lorenzo Valley Water District | California | 22,610 | 1 | 1 | 23% | 15% | 2024-10-17 |
| 98 | City of Dinuba | California | 22,497 | 1 | 1 | 89% | 51% | 2024-10-17 |
| 99 | City of Oakdale | California | 21,894 | 1 | 1 | 39% | 24% | 2024-10-17 |
| 100 | City of Safford | Arizona | 21,521 | 1 | 1 | 40% | 33% | 2025-10-02 |
How to read this ranking
Each row links to a full utility profile with violation history, lead testing results, and service-area ZIPs. The demographic context columns are from independent data sources (ACS, not EJScreen) and are provided for readers who want to examine equity patterns alongside the operational data.
See the full methodology for calculation details, data vintages, and known limitations.
Frequently asked questions
What is an unresolved health-based violation?
A violation of a federal Safe Drinking Water Act standard (Maximum Contaminant Level, Treatment Technique, or Monitoring requirement for a health-based contaminant) that has not been formally returned to compliance in EPA records. These reflect ongoing public-health concerns documented in EPA's ECHO enforcement database.
Why show demographic context next to violations?
Federal Safe Drinking Water Act data does not distinguish between communities by race or income — violations are violations regardless of who is served. We publish demographic columns so readers can independently examine whether specific systems with long-running violations also serve disproportionately low-income or non-white populations. We do not claim causation; we report two independent facts side by side.
Are these the most dangerous water systems in the country?
Not necessarily. "Unresolved" counts procedural and technical violations alongside contaminant exceedances. A high count indicates a system that federal regulators have flagged repeatedly without resolution. For any specific system, click through to its profile page for the individual violations on record.
Where does the data come from?
Violation records come from EPA's Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database, refreshed weekly. Demographic context comes from the U.S. Census American Community Survey (ACS) 5-year estimates (2019-2023), aggregated from block-group level to utility-level using EPA's Community Water System Service Area Boundaries v3 population weights.
ZipCheckup is an independent public-data tool. We are a referral service and do not provide water testing, remediation, or utility services. Rankings reflect publicly-available federal data and are provided for informational purposes. For issues with your specific water system, contact your local water utility or state drinking water program.