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Our complete water quality ranking grades 39 U.S. states A–F using EPA data. See which states have the best and worst tap water, each state's average safety score, and the top-ranked city within it. Click any state to explore all cities and detailed water quality data.
Based on the average EPA-record score of every city we can grade (health-based violations, lead results, PFAS monitoring — see the methodology), the states with the best water quality are New Mexico (grade A, avg 100/100), Virginia (grade A, avg 100/100), Arkansas (grade A, avg 99/100), Hawaii (grade A, avg 99/100), and Oklahoma (grade A, avg 99/100). These states tend to pair cleaner source water and modern treatment with strong EPA compliance records. See the full ranking of all 39 states below.
Which states have the worst water quality? The lowest state averages are New York (grade C, avg 72/100), Florida (grade C, avg 77/100) and Arizona (grade B, avg 81/100). A low state average means several graded cities lost points for health-based EPA violations, lead results or PFAS detections — it does not mean every city in the state is unsafe. Check the city grade where you live.
A state average blends hundreds of separate water systems, and it says nothing about your home's own plumbing. Even in a top-graded state, lead and copper can leach from your home's own pipes after the water reaches your street — which no statewide score can capture.
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Click any state to explore all cities and detailed water quality data
| Rank | State | Avg Score | Grade | Cities | Score Range | Population |
|---|---|---|---|---|---|---|
| #1 | New Mexico | 100 | A | 1 | 100 - 100 | 560,326 |
| #2 | Virginia | 100 | A | 1 | 100 - 100 | 233,655 |
| #3 | Arkansas | 99 | A | 18 | 90 - 100 | 1,336,100 |
| #4 | Hawaii | 99 | A | 4 | 98 - 100 | 911,693 |
| #5 | Oklahoma | 99 | A | 2 | 98 - 100 | 1,057,000 |
| #6 | Tennessee | 99 | A | 2 | 97 - 100 | 1,437,653 |
| #7 | Michigan | 98 | A | 3 | 97 - 100 | 1,074,175 |
| #8 | Minnesota | 97 | A | 1 | 97 - 97 | 425,300 |
| #9 | Missouri | 97 | A | 2 | 95 - 98 | 1,664,295 |
| #10 | Wisconsin | 97 | A | 1 | 97 - 97 | 626,000 |
| #11 | Iowa | 96 | A | 24 | 72 - 100 | 1,470,797 |
| #12 | Nevada | 96 | A | 1 | 96 - 96 | 1,539,277 |
| #13 | Colorado | 94 | A | 35 | 64 - 100 | 4,742,845 |
| #14 | Maine | 94 | A | 11 | 74 - 100 | 363,476 |
| #15 | Indiana | 93 | A | 32 | 59 - 100 | 2,918,159 |
| #16 | Kentucky | 93 | A | 23 | 71 - 100 | 2,544,635 |
| #17 | Oregon | 93 | A | 3 | 79 - 100 | 1,042,020 |
| #18 | Utah | 93 | A | 7 | 84 - 100 | 1,007,311 |
| #19 | Louisiana | 91 | A | 22 | 57 - 100 | 1,949,658 |
| #20 | Massachusetts | 91 | A | 48 | 57 - 100 | 3,750,575 |
| #21 | Idaho | 90 | A | 20 | 70 - 100 | 1,056,251 |
| #22 | Illinois | 90 | A | 56 | 55 - 100 | 6,217,785 |
| #23 | Kansas | 90 | A | 20 | 55 - 100 | 1,341,797 |
| #24 | Alaska | 89 | B | 10 | 73 - 100 | 400,096 |
| #25 | California | 89 | B | 163 | 34 - 100 | 26,652,064 |
| #26 | Nebraska | 89 | B | 1 | 89 - 89 | 660,000 |
| #27 | Washington | 89 | B | 4 | 74 - 100 | 2,327,316 |
| #28 | Maryland | 88 | B | 15 | 64 - 100 | 4,521,145 |
| #29 | Connecticut | 87 | B | 18 | 71 - 100 | 1,939,787 |
| #30 | Delaware | 87 | B | 9 | 74 - 100 | 246,287 |
| #31 | Georgia | 86 | B | 27 | 33 - 100 | 4,367,870 |
| #32 | North Carolina | 85 | B | 5 | 72 - 100 | 2,858,679 |
| #33 | Ohio | 85 | B | 5 | 74 - 99 | 4,005,101 |
| #34 | Pennsylvania | 84 | B | 4 | 69 - 100 | 2,624,001 |
| #35 | Alabama | 82 | B | 22 | 52 - 100 | 2,565,357 |
| #36 | Texas | 82 | B | 11 | 68 - 96 | 11,353,130 |
| #37 | Arizona | 81 | B | 37 | 44 - 100 | 5,364,504 |
| #38 | Florida | 77 | C | 87 | 21 - 100 | 12,503,302 |
| #39 | New York | 72 | C | 5 | 29 - 98 | 9,160,569 |
Water quality varies significantly by region due to geography, source water, infrastructure age, and environmental factors:
New Mexico ranks #1 with an average water quality rating of 100/100 (grade A) across 1 graded city; its top-rated city is Albuquerque at 100/100. The rest of the top five are Virginia (100/100), Arkansas (99/100), Hawaii (99/100), Oklahoma (99/100).
New York has the lowest state average in our 2026 rankings at 72/100 (grade C) across 5 graded cities. A low average means some cities lost points for health-based EPA violations, lead results or PFAS detections. It does not mean every city in the state is unsafe, so check your own city's grade.
Each city gets a 0–100 score from public EPA records: health-based and monitoring Safe Drinking Water Act violations over the last five years, recent Lead and Copper Rule 90th-percentile results, and UCMR5 PFAS sampling. Scores of 90+ earn an A, 80–89 a B, 70–79 a C, 60–69 a D and below 60 an F. A state's rating is the average score of its graded cities.
This 2026 ranking covers the 39 states where we can grade at least one city from complete EPA records (760 graded cities in total). States where we have not yet matched a city's water system to EPA's federal SDWIS records are left out rather than given an estimated grade.