PlainWater

Water Quality by State

Compare drinking water systems, violations, and PFAS testing across all 50 states and territories, using EPA SDWIS and UCMR5 data. See our methodology.

Coverage status: EPA SDWIS, every U.S. state, DC, and applicable territories included. 66 jurisdictions in the current release.

State Systems Population Violations Violation Rate PFAS Tested PFAS Detected
Alabama 562 6,193,356 40,486 98.6% 306 117
Alaska 1,326 862,218 267,144 97.9% 30 9
American Samoa 91 50,626 1,883 22% 1 1
Arizona 1,493 7,322,166 228,944 98.4% 152 57
Arkansas 1,016 3,049,400 53,437 94.5% 172 10
California 7,249 42,404,883 153,308 89.2% 694 231
Colorado 2,193 7,473,456 238,796 92.6% 163 37
Connecticut 2,332 2,886,005 206,662 94% 63 40
Delaware 460 1,083,630 9,105 74.8% 35 17
District of Columbia 5 667,575 263 100% 3 3
EPA Region 1 — Tribal Water Systems 5 58,570 814 100% 2 1
EPA Region 10 — Tribal Water Systems 158 142,574 31,953 98.1% 10 0
EPA Region 2 — Tribal Water Systems 9 12,762 579 100% 2 0
EPA Region 4 — Tribal Water Systems 30 69,141 1,215 86.7% 2 0
EPA Region 5 — Tribal Water Systems 113 144,290 19,546 94.7% 13 1
EPA Region 6 — Tribal Water Systems 89 196,087 4,905 97.8% 18 2
EPA Region 7 — Tribal Water Systems 19 14,784 2,342 57.9% 1 0
EPA Region 8 — Tribal Water Systems 160 144,980 13,068 96.3% 13 1
EPA Region 9 — Tribal Water Systems 323 555,721 48,296 96.6% 41 8
Florida 5,093 22,381,282 184,355 93.2% 402 190
Georgia 2,382 10,694,477 108,966 92.1% 254 77
Guam 8 327,417 203 100% 5 3
Hawaii 137 1,520,931 5,234 80.3% 45 2
Idaho 2,005 1,743,912 104,850 96.1% 60 8
Illinois 5,117 12,576,876 355,322 80.8% 487 123
Indiana 3,967 5,774,616 352,710 95.8% 229 55
Iowa 1,795 3,114,444 138,271 95.2% 152 32
Kansas 957 2,894,673 84,344 99.1% 103 34
Kentucky 424 4,570,541 80,482 99.1% 231 87
Louisiana 1,234 5,316,532 115,060 92.5% 265 47
Maine 1,864 936,624 148,796 93.6% 41 10
Maryland 3,215 6,070,211 60,496 79.9% 83 30
Massachusetts 1,599 10,332,845 73,886 95.2% 263 143
Michigan 10,959 9,098,093 255,201 86.1% 318 44
Minnesota 6,557 5,239,398 59,895 51.6% 196 87
Mississippi 1,185 3,286,781 499,292 96.1% 238 9
Missouri 2,823 5,855,885 201,695 95.4% 230 71
Montana 2,263 1,112,267 297,270 94.7% 45 5
Navajo Nation 170 167,275 29,535 100% 13 2
Nebraska 1,309 1,798,088 49,989 88.9% 53 7
Nevada 589 3,455,285 56,333 92.5% 57 10
New Hampshire 2,453 1,242,123 155,970 90.2% 51 18
New Jersey 3,428 9,570,926 204,988 95% 264 172
New Mexico 1,037 2,027,497 154,522 96.9% 72 10
New York 8,098 19,294,951 552,003 94.4% 332 98
North Carolina 5,020 9,877,724 524,053 92.9% 287 143
North Dakota 368 712,349 13,624 94% 38 7
Northern Mariana Islands 60 70,193 4,377 98.3% 2 1
Ohio 4,181 11,085,226 288,388 90.4% 346 141
Oklahoma 1,262 3,699,452 336,706 98.2% 166 61
Oregon 2,518 4,005,242 206,659 98.5% 125 18
Pennsylvania 7,701 12,630,061 1,159,868 97.1% 389 173
Puerto Rico 458 3,328,141 164,144 99.6% 99 38
Rhode Island 463 1,159,492 33,766 95.9% 29 15
South Carolina 1,390 4,709,324 38,355 65.3% 164 90
South Dakota 654 915,901 56,254 91.6% 49 7
Tennessee 762 7,934,203 43,318 94% 277 87
Texas 7,351 33,253,313 746,210 90.2% 1,147 610
US Virgin Islands 256 122,604 1,317 83.6% 3 1
Utah 1,068 3,870,776 169,784 97.6% 129 16
Vermont 1,357 646,999 153,729 93% 37 3
Virginia 2,821 7,911,199 146,670 90% 171 54
Washington 4,557 9,736,844 314,648 92.1% 247 66
West Virginia 774 1,597,057 187,590 99.5% 102 34
Wisconsin 10,988 5,131,439 285,161 72.1% 202 51
Wyoming 766 639,288 32,465 94.5% 33 3

Download the SDWIS/UCMR5 state landscape snapshot cited on this page: sdwis-state-landscape.csv (same CSV as /statistics, CC0).