Cities with the Most Health-Based Water Violations

These cities have the most health-based water violations, meaning contaminants were found above EPA Maximum Contaminant Levels. Health violations represent the most serious category of drinking water problems because they indicate potential direct health risks.

# ▴▾ City ▴▾ State ▴▾ Health Viol. ▴▾ Total Viol. ▴▾ Population ▴▾
1 Des Peres TX 1,817 12,153 30,946
2 Lubbock TX 1,353 3,957 276,842
3 Brady TX 1,157 1,222 5,434
4 Austin TX 1,147 12,912 1,788,805
5 Cypress TX 873 5,741 75,711
6 Sacramento CA 869 1,022 1,219,532
7 Wichita Falls TX 824 990 118,265
8 Mcalester OK 784 1,248 28,783
9 Waukesha WI 783 934 72,340
10 Houston TX 745 13,053 5,913,001
11 Huntington TX 710 3,010 9,721
12 Livingston TX 672 1,676 47,492
13 Wewoka OK 669 874 4,352
14 Bakersfield CA 632 923 137,162
15 Farmerville LA 628 889 12,351
16 West Monroe LA 611 802 116,661
17 Coalinga CA 570 599 18,440
18 Hominy OK 563 821 2,584
19 Zwolle LA 524 613 11,862
20 Barnsdall OK 521 776 1,804
21 Vidor TX 514 1,295 16,653
22 Shallowater TX 512 4,335 3,241
23 Des Peres AZ 508 3,091 14,744
24 Springer NM 505 738 1,514
25 Maricopa AZ 498 2,061 117,033
26 Fresno CA 484 903 630,234
27 Wolfforth TX 477 4,690 9,789
28 Fairfax OK 472 667 1,655
29 San Bernardino CA 470 544 377,910
30 Madera CA 470 818 85,851
31 Salinas CA 439 567 64,442
32 Boswell OK 438 554 1,782
33 Clayton OK 436 563 2,226
34 La Junta CO 420 629 10,097
35 Nowata OK 418 767 7,101
36 Ferriday LA 416 537 13,181
37 Manzanola CO 413 651 967
38 Wiley CO 412 617 1,905
39 Many LA 412 620 20,592
40 Eufaula OK 405 701 13,284
41 Checotah OK 405 542 11,036
42 Anchorage AK 382 6,388 249,201
43 Valdosta GA 382 957 77,511
44 Muskogee OK 379 452 43,745
45 Chico CA 378 639 23,374
46 Maysville OK 378 517 1,212
47 Morris OK 357 455 5,750
48 Winnfield LA 349 397 12,090
49 Freeport TX 343 841 15,123
50 Cleveland OK 340 433 6,844

Key Takeaways

  • Health-based violations mean a regulated contaminant was measured above the EPA's safe limit.
  • Cities with many health violations may have specific persistent contamination issues.
  • The number of health violations does not directly indicate current water quality — many may have been resolved.

Methodology

Data is sourced from the EPA Safe Drinking Water Information System (SDWIS) via the Envirofacts API. Rankings include community water systems serving 100 or more people. Violation counts reflect historical records in the SDWIS database and include both resolved and unresolved violations. Health-based violations include Maximum Contaminant Level (MCL) violations and Treatment Technique violations. Per-capita calculations use the total population served by tracked water systems in each state.

Verify data at epa.gov