Drinking-water safety · % of systems in violation
States Where the Most Water Systems Are in Violation
Share of each state's community water systems with a health-based violation since 2016 — a size-adjusted look at drinking-water trouble.
Oklahoma leads "States Where the Most Water Systems Are in Violation" at 73.9%.
| # | State / item | % of systems in violation |
|---|---|---|
| 1 | Oklahoma 653 of 884 | 73.9% |
| 2 | New Mexico 407 of 592 | 68.8% |
| 3 | Louisiana 517 of 819 | 63.1% |
| 4 | West Virginia 260 of 430 | 60.5% |
| 5 | Alaska 242 of 405 | 59.8% |
| 6 | Kentucky 179 of 375 | 47.7% |
| 7 | Arizona 414 of 954 | 43.4% |
| 8 | Nevada 98 of 232 | 42.2% |
| 9 | Pennsylvania 724 of 1,782 | 40.6% |
| 10 | Utah 220 of 558 | 39.4% |
| 11 | Connecticut 192 of 504 | 38.1% |
| 12 | Wisconsin 370 of 977 | 37.9% |
| 13 | Texas 1,723 of 4,617 | 37.3% |
| 14 | Arkansas 237 of 666 | 35.6% |
| 15 | Colorado 394 of 1,113 | 35.4% |
Method: Limited to states with at least 50 community water systems.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1 refresh; violations since 2016