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 5,909 medium and large community water systems with sufficient data, these 100 utilities carry the most open federal health-based violations in EPA's enforcement records. The list is sorted by unresolved 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. (5yr) | % PoC served | % Below 200% FPL | Last violation |
|---|---|---|---|---|---|---|---|---|
| 1 | City of Brady Water System | Texas | 4,964 | 94 | 112 | 39% | 34% | 2025-10-01 |
| 2 | Muskogee Company RWD #5 | Oklahoma | 4,161 | 45 | 45 | 45% | 43% | 2025-10-01 |
| 3 | Waukesha Water Utility | Wisconsin | 62,014 | 43 | 56 | 19% | 19% | 2024-10-01 |
| 4 | Hugo Municipal Authority | Oklahoma | 4,293 | 43 | 46 | 45% | 49% | 2025-07-01 |
| 5 | Town of Ferriday Water System | Louisiana | 3,553 | 32 | 36 | 57% | 56% | 2025-10-01 |
| 6 | City of Lindsay | California | 10,929 | 32 | 33 | 86% | 51% | 2025-10-01 |
| 7 | Southern Okla Water Corporation | Oklahoma | 9,998 | 32 | 32 | 35% | 37% | 2025-07-01 |
| 8 | Tecumseh Utility Authority | Oklahoma | 4,826 | 31 | 31 | 28% | 39% | 2025-09-29 |
| 9 | Coweta PWA | Oklahoma | 6,194 | 29 | 33 | 31% | 27% | 2025-10-01 |
| 10 | Franklin Water Supply | Louisiana | 8,444 | 29 | 31 | 55% | 45% | 2025-06-21 |
| 11 | Marshall County Rural Water District #2 | Oklahoma | 5,059 | 29 | 29 | 33% | 41% | 2025-07-01 |
| 12 | Las Vegas (City of) | New Mexico | 14,345 | 27 | 46 | 84% | 45% | 2025-08-01 |
| 13 | Lowndes Company-North Lowndes Company Ws | Georgia | 3,632 | 26 | 26 | 37% | 32% | 2025-07-01 |
| 14 | Adamson RWD #8 | Oklahoma | 4,330 | 25 | 25 | 35% | 40% | 2024-10-01 |
| 15 | Poteau PWA | Oklahoma | 6,674 | 24 | 25 | 30% | 44% | 2025-10-01 |
| 16 | Orange County Wcid 1 | Texas | 10,436 | 22 | 22 | 12% | 28% | 2025-10-01 |
| 17 | Okmulgee Company RWD #6 (Hectorville) | Oklahoma | 6,323 | 22 | 22 | 30% | 27% | 2025-04-01 |
| 18 | Okmulgee | Oklahoma | 11,316 | 21 | 23 | 46% | 48% | 2025-10-01 |
| 19 | City of Hughson | California | 6,241 | 21 | 21 | 44% | 23% | 2025-07-01 |
| 20 | Pewaukee Village Waterworks | Wisconsin | 4,427 | 21 | 21 | 11% | 11% | 2025-11-19 |
| 21 | Wagoner Company RWD #4 | Oklahoma | 24,876 | 20 | 29 | 33% | 23% | 2025-07-01 |
| 22 | Belen Water System | New Mexico | 6,293 | 18 | 24 | 69% | 45% | 2025-12-21 |
| 23 | Herkimer Village | New York | 3,517 | 18 | 19 | 10% | 33% | 2025-11-02 |
| 24 | Inver Grove Heights | Minnesota | 21,108 | 18 | 18 | 25% | 15% | 2025-10-01 |
| 25 | Kingfisher | Oklahoma | 4,655 | 17 | 17 | 25% | 27% | 2025-10-01 |
| 26 | Altus | Oklahoma | 15,763 | 16 | 20 | 40% | 39% | 2025-04-01 |
| 27 | Rogers Company RWD # 3 Lake Plant | Oklahoma | 24,464 | 16 | 16 | 30% | 25% | 2025-07-01 |
| 28 | City of Jackson | Mississippi | 138,024 | 15 | 21 | 84% | 50% | 2025-04-01 |
| 29 | Maxwell Special Utility District | Texas | 9,122 | 15 | 17 | 61% | 38% | 2025-04-01 |
| 30 | R. C. Willis WTP (City of Palatka) | Florida | 7,653 | 15 | 15 | 38% | 51% | 2025-04-01 |
| 31 | Baldwin County | Georgia | 4,179 | 14 | 18 | 48% | 41% | 2025-07-01 |
| 32 | City of Dos Palos | California | 7,477 | 14 | 14 | 82% | 52% | 2025-07-01 |
| 33 | Union County Water District | Kentucky | 4,668 | 13 | 16 | 13% | 39% | 2025-10-01 |
| 34 | City of Lemoore | California | 25,315 | 13 | 13 | 63% | 34% | 2025-07-02 |
| 35 | Camino Real Regional Utility Authority | New Mexico | 9,903 | 12 | 28 | 95% | 61% | 2025-01-01 |
| 36 | Perry Water & Light Department | Oklahoma | 4,079 | 12 | 17 | 13% | 32% | 2025-07-01 |
| 37 | Mcalester PWA | Oklahoma | 7,162 | 12 | 16 | 33% | 40% | 2025-10-01 |
| 38 | City of Port Lavaca | Texas | 9,899 | 12 | 14 | 64% | 32% | 2025-10-24 |
| 39 | Maysville Regional Water | Ohio | 4,161 | 11 | 16 | 11% | 38% | 2025-10-01 |
| 40 | Mansfield Water System | Louisiana | 4,045 | 11 | 15 | 72% | 60% | 2025-03-01 |
| 41 | Webb County Water Utilities | Texas | 7,513 | 11 | 14 | 98% | 55% | 2025-10-01 |
| 42 | City of Bogalusa Water System | Louisiana | 7,294 | 11 | 12 | 43% | 49% | 2025-07-01 |
| 43 | Grinnell Water Department | Iowa | 8,703 | 11 | 11 | 11% | 26% | 2025-04-01 |
| 44 | Raleigh County Public Service District Arnett | West Virginia | 3,374 | 11 | 11 | 13% | 43% | 2025-11-06 |
| 45 | Pender County Utilities | North Carolina | 7,645 | 10 | 13 | 34% | 31% | 2025-10-01 |
| 46 | Mountain Water District | Kentucky | 27,012 | 10 | 10 | 5% | 48% | 2025-10-01 |
| 47 | Leflore Company RWD #14 | Oklahoma | 7,353 | 10 | 10 | 31% | 47% | 2023-04-01 |
| 48 | Mingo County Public Service District - Naugatuck | West Virginia | 4,110 | 10 | 10 | 5% | 51% | 2025-11-15 |
| 49 | Tallulah Water System | Louisiana | 5,558 | 9 | 24 | 71% | 62% | 2025-07-02 |
| 50 | Truth Or Consequences | New Mexico | 6,039 | 9 | 17 | 41% | 57% | 2025-11-30 |
| 51 | Bethlehem Water District No 1 | New York | 13,972 | 9 | 13 | 13% | 11% | 2024-10-01 |
| 52 | Lake Livingston Pineshadows East | Texas | 3,441 | 9 | 12 | 27% | 36% | 2025-05-01 |
| 53 | City of Clyde | Texas | 3,424 | 9 | 12 | 21% | 28% | 2025-07-01 |
| 54 | City of Marlin | Texas | 4,758 | 9 | 11 | 70% | 57% | 2025-10-01 |
| 55 | Grambling Water System | Louisiana | 3,903 | 9 | 11 | 73% | 69% | 2025-11-18 |
| 56 | Milltown W Department | New Jersey | 3,506 | 9 | 11 | 25% | 16% | 2026-01-01 |
| 57 | Gbra Calhoun County Rural Water System | Texas | 4,431 | 9 | 10 | 64% | 32% | 2025-10-31 |
| 58 | City of Jackson-Maddox Rd. | Mississippi | 10,350 | 9 | 9 | 50% | 28% | 2025-07-01 |
| 59 | Pewaukee City Water and Sewer Utility | Wisconsin | 5,124 | 9 | 9 | 13% | 12% | 2025-10-01 |
| 60 | Rayville Water System | Louisiana | 3,326 | 9 | 9 | 40% | 49% | 2025-10-01 |
| 61 | Hudson Water Supply Corporation | Texas | 7,764 | 8 | 14 | 41% | 38% | 2025-10-01 |
| 62 | Central Washington County Water Supply Corporation | Texas | 5,245 | 8 | 12 | 39% | 28% | 2025-07-01 |
| 63 | Nyack Village Water Supply | New York | 11,609 | 8 | 10 | 41% | 14% | 2025-01-01 |
| 64 | Comanche Company RWD #4 | Oklahoma | 4,938 | 8 | 9 | 31% | 30% | 2025-09-29 |
| 65 | Battle Creek - Verona System | Michigan | 52,508 | 8 | 8 | 29% | 38% | 2025-10-01 |
| 66 | Somerset Water Department | Massachusetts | 17,769 | 8 | 8 | 8% | 11% | 2023-07-01 |
| 67 | Jefferson Company Cons RWD #1 | Oklahoma | 8,202 | 8 | 8 | 20% | 40% | 2023-01-01 |
| 68 | Jefferson Waterworks | Wisconsin | 5,720 | 8 | 8 | 17% | 19% | 2024-10-01 |
| 69 | City of Gladstone | Oregon | 5,305 | 8 | 8 | 22% | 22% | 2025-10-01 |
| 70 | Badger Mountain Irrigation District | Washington | 3,802 | 8 | 8 | 27% | 18% | 2024-01-01 |
| 71 | Shreveport Water System | Louisiana | 160,108 | 7 | 20 | 61% | 45% | 2025-10-01 |
| 72 | Veolia Water New York | New York | 287,204 | 7 | 12 | 40% | 30% | 2025-07-01 |
| 73 | Thomson-Mcduffie Co W&S Comm | Georgia | 6,884 | 7 | 12 | 51% | 38% | 2025-07-01 |
| 74 | City of Perry | Florida | 3,793 | 7 | 11 | 30% | 47% | 2025-01-01 |
| 75 | Edgecombe Water & Sewer District | North Carolina | 20,826 | 7 | 8 | 58% | 40% | 2025-07-01 |
| 76 | Jefferson Twp W U Lk Hop | New Jersey | 4,611 | 7 | 8 | 30% | 11% | 2025-10-11 |
| 77 | Town of Haughton Water System | Louisiana | 3,872 | 7 | 8 | 25% | 41% | 2025-08-16 |
| 78 | Watertown City | New York | 24,285 | 7 | 7 | 18% | 36% | 2025-12-01 |
| 79 | Milltown-Washburn Water Users | Arkansas | 4,729 | 7 | 7 | 13% | 30% | 2023-04-01 |
| 80 | Tracy City Water System | Tennessee | 3,851 | 7 | 7 | 6% | 36% | 2025-10-01 |
| 81 | City of Gladewater | Texas | 3,621 | 6 | 13 | 28% | 35% | 2025-11-17 |
| 82 | Berryville, Town of | Virginia | 4,145 | 6 | 9 | 16% | 17% | 2025-01-01 |
| 83 | City of Nederland | Texas | 17,150 | 6 | 8 | 23% | 26% | 2025-10-01 |
| 84 | Wilderness | Virginia | 3,301 | 6 | 8 | 27% | 13% | 2024-10-01 |
| 85 | Lincoln Park Water Department | New Jersey | 5,115 | 6 | 7 | 27% | 13% | 2025-10-01 |
| 86 | Riverside Special Utility District | Texas | 3,645 | 6 | 7 | 47% | 44% | 2025-10-01 |
| 87 | Calcasieu Parish Ww District No 4 | Louisiana | 3,620 | 6 | 7 | 18% | 35% | 2025-12-06 |
| 88 | Aiken City of (0210001) | South Carolina | 42,344 | 6 | 6 | 37% | 31% | 2021-07-01 |
| 89 | Lake Utility Services Inc. North (8 Wps) | Florida | 32,389 | 6 | 6 | 45% | 23% | 2022-05-01 |
| 90 | Bryan County Rural Water District #5 | Oklahoma | 7,648 | 6 | 6 | 33% | 42% | 2023-01-01 |
| 91 | Hartsville-Trousdale W&S U.D. | Tennessee | 6,326 | 6 | 6 | 17% | 25% | 2025-01-01 |
| 92 | City of Avenal | California | 4,483 | 6 | 6 | 92% | 58% | 2024-10-17 |
| 93 | Village Water System | Louisiana | 7,222 | 5 | 19 | 29% | 43% | 2024-07-01 |
| 94 | City of Big Spring | Texas | 22,935 | 5 | 17 | 55% | 31% | 2025-10-01 |
| 95 | Hamlet Water System | North Carolina | 6,180 | 5 | 15 | 43% | 51% | 2025-05-01 |
| 96 | Chickasha Municipal Authority | Oklahoma | 14,635 | 5 | 13 | 26% | 38% | 2024-10-17 |
| 97 | Winnsboro Water System | Louisiana | 4,426 | 5 | 11 | 39% | 52% | 2025-11-11 |
| 98 | Salem Water Works | Indiana | 5,316 | 5 | 10 | 4% | 41% | 2025-07-01 |
| 99 | Wallkill Consolidated Water District | New York | 16,679 | 5 | 8 | 59% | 22% | 2024-10-17 |
| 100 | Bedford County U.D. | Tennessee | 12,383 | 5 | 8 | 26% | 35% | 2023-08-01 |
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.