States with the Most Health-Based Water Violations

Health-based violations occur when a contaminant exceeds the EPA's Maximum Contaminant Level (MCL) or when a required treatment technique is not followed. These represent the most serious category of drinking water violations because they indicate potential health risks to consumers.

# ▴▾ State ▴▾ Health Violations ▴▾ Total Violations ▴▾ Water Systems ▴▾ Population ▴▾
1 Texas 39,140 263,180 4,713 32,406,355
2 Oklahoma 29,472 128,472 889 3,653,817
3 California 18,881 39,276 2,819 40,093,669
4 Louisiana 16,153 32,039 917 5,225,688
5 New Mexico 7,761 37,115 555 1,923,604
6 Arkansas 6,234 17,031 665 3,019,237
7 Pennsylvania 6,042 199,265 1,855 11,468,960
8 New York 5,682 93,834 2,245 18,268,008
9 Colorado 5,256 42,596 1,048 7,175,420
10 Alaska 5,020 73,527 405 699,435
11 Arizona 4,414 60,414 751 7,093,233
12 Missouri 3,923 25,377 1,431 5,651,462
13 Kansas 3,703 19,480 856 2,869,691
14 North Carolina 3,287 54,399 1,979 9,538,792
15 Illinois 3,286 30,544 1,782 12,123,082
16 Georgia 3,145 32,159 1,739 10,561,974
17 Florida 3,132 36,335 1,593 21,963,405
18 West Virginia 2,703 81,622 412 1,546,947
19 Virginia 2,604 15,298 1,062 7,437,928
20 Idaho 2,547 26,078 764 1,565,041
21 Wisconsin 2,518 18,533 1,021 4,230,296
22 Washington 2,509 54,459 2,311 9,192,864
23 Mississippi 2,328 25,296 1,012 3,200,594
24 Nebraska 2,253 5,134 585 1,706,785
25 Kentucky 1,801 9,427 374 4,556,638
26 Indiana 1,720 18,261 771 5,231,741
27 New Hampshire 1,699 6,968 710 920,024
28 Vermont 1,306 12,362 405 466,945
29 Montana 1,220 20,202 792 789,179
30 Michigan 1,211 15,820 1,381 7,509,650
31 Nevada 1,162 8,167 192 3,119,117
32 New Jersey 1,125 19,332 555 8,881,952
33 Massachusetts 937 10,561 525 10,050,324
34 Iowa 934 9,389 1,076 3,000,306
35 Maine 913 6,830 387 691,040
36 Wyoming 742 13,783 323 536,350
37 Minnesota 733 3,784 965 4,670,079
38 Connecticut 729 28,800 475 2,726,278
39 Maryland 594 5,321 461 5,523,173
40 Alabama 471 13,972 501 6,168,671
41 Delaware 314 1,242 207 1,018,198
42 Hawaii 44 182 119 1,507,224
43 District of Columbia 23 115 4 667,325
44 North Dakota 0 8,431 318 743,065
45 Ohio 0 61,604 1,094 10,443,946
46 Oregon 0 0 0 0
47 Rhode Island 0 0 0 0
48 South Carolina 0 13,045 557 4,631,800
49 South Dakota 0 19,565 512 927,151
50 Tennessee 0 20,607 453 7,862,060
51 Utah 0 71,655 559 3,702,006

Key Takeaways

  • Health-based violations are a subset of total violations and represent the most serious water quality problems.
  • Some states with many total violations may have relatively few health-based ones, indicating mostly monitoring or reporting issues.
  • States with zero health violations may have incomplete data or different enforcement practices.

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