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Our complete water quality ranking grades all 50 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.
Even states with solid average scores can have cities with lead pipes, PFAS, or arsenic above EPA limits. A certified water filter removes the specific contaminants in your local water — no matter where your state ranks on the A–F scale.
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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 | Michigan | 95 | A+ | 3 | 95 - 95 | 4,435,000 |
| #2 | Minnesota | 95 | A+ | 1 | 95 - 95 | 420,000 |
| #3 | Missouri | 95 | A+ | 2 | 95 - 95 | 1,730,000 |
| #4 | Nebraska | 95 | A+ | 1 | 95 - 95 | 500,000 |
| #5 | Nevada | 95 | A+ | 1 | 95 - 95 | 2,300,000 |
| #6 | New Mexico | 95 | A+ | 1 | 95 - 95 | 680,000 |
| #7 | Ohio | 95 | A+ | 5 | 95 - 95 | 4,400,000 |
| #8 | Oklahoma | 95 | A+ | 2 | 95 - 95 | 1,180,000 |
| #9 | Oregon | 95 | A+ | 3 | 95 - 95 | 200,051 |
| #10 | Utah | 95 | A+ | 8 | 95 - 95 | 1,670,000 |
| #11 | Washington | 95 | A+ | 4 | 95 - 95 | 2,430,000 |
| #12 | Wisconsin | 95 | A+ | 1 | 95 - 95 | 820,000 |
| #13 | New York | 93 | A | 5 | 86 - 95 | 11,141,000 |
| #14 | North Carolina | 92 | A | 5 | 86 - 95 | 2,186,176 |
| #15 | Pennsylvania | 91 | A | 4 | 78 - 95 | 2,230,380 |
| #16 | Texas | 88 | A- | 11 | 65 - 97 | 9,176,377 |
| #17 | Alabama | 83 | B+ | 25 | 68 - 96 | 1,710,306 |
| #18 | Arkansas | 83 | B+ | 20 | 69 - 97 | 1,154,104 |
| #19 | Delaware | 83 | B+ | 10 | 59 - 95 | 218,074 |
| #20 | Iowa | 83 | B+ | 25 | 64 - 96 | 1,419,752 |
| #21 | Maine | 83 | B+ | 15 | 69 - 95 | 375,765 |
| #22 | Maryland | 83 | B+ | 35 | 50 - 98 | 2,233,992 |
| #23 | Massachusetts | 83 | B+ | 50 | 54 - 96 | 3,750,253 |
| #24 | Connecticut | 82 | B+ | 25 | 67 - 97 | 1,602,775 |
| #25 | Hawaii | 81 | B+ | 15 | 67 - 92 | 778,599 |
| #26 | Indiana | 81 | B+ | 40 | 46 - 97 | 3,126,303 |
| #27 | Kentucky | 81 | B+ | 30 | 46 - 97 | 1,715,759 |
| #28 | Tennessee | 81 | B+ | 2 | 67 - 95 | 7,922 |
| #29 | California | 80 | B+ | 193 | 44 - 98 | 28,240,268 |
| #30 | Kansas | 80 | B+ | 25 | 48 - 97 | 1,722,561 |
| #31 | Arizona | 79 | B | 40 | 51 - 98 | 5,474,285 |
| #32 | Illinois | 79 | B | 60 | 47 - 98 | 6,321,081 |
| #33 | Alaska | 78 | B | 10 | 56 - 93 | 410,660 |
| #34 | Florida | 78 | B | 96 | 47 - 96 | 8,727,925 |
| #35 | Georgia | 78 | B | 40 | 44 - 96 | 2,901,545 |
| #36 | Idaho | 78 | B | 20 | 66 - 95 | 1,011,043 |
| #37 | Louisiana | 77 | B | 30 | 52 - 96 | 1,708,978 |
| #38 | Virginia | 77 | B | 1 | 77 - 77 | 229,395 |
| #39 | Colorado | 76 | B | 35 | 45 - 96 | 3,675,915 |
Water quality varies significantly by region due to geography, source water, infrastructure age, and environmental factors:
Based on 2026 EPA data, Michigan ranks #1 with an average score of 95/100 (Grade A+) across 3 cities. The highest-rated city in Michigan is Detroit (95/100). States with protected watersheds, modern treatment plants, and strong EPA compliance records consistently rank highest.
Colorado has the lowest average water quality score of the 39 states analyzed — 76/100 (Grade B) across 35 cities. Residents in lower-ranked states should consider a certified water filter matched to the specific contaminants detected in their city.
100% of the 39 states analyzed score 75 or higher (Grade B or better), indicating generally good water quality. The national average is 86/100. However, quality varies significantly by location — a high state average can hide wide variation between individual cities. Always check your specific city's report for the most accurate picture.
State rankings aggregate the scores of every tracked public water system within the state. Each city score is based on three weighted factors: how far detected contaminants fall below EPA maximum limits, the utility's EPA compliance and violation history, and infrastructure age. Because water is managed locally, quality can vary widely between cities in the same state — click any state to see a full city-by-city breakdown.