Tap water quality in every state
Tap Water Quality averages 84.5/100 nationally. But real averages run from 99.9/100 in Hawaii to 72.6/100 in Oklahoma. The score is population-weighted from city-level EPA violation data — 100 means no contaminants above EPA limits or health guidelines. The violations column counts health-based violations per community water system in 2024.
All states ranked, best to worst tap water
Quality scores: TapWaterData 2026 state rankings, population-weighted from EPA SDWIS violation data across 9,500+ cities (100 = no contaminants exceeding EPA limits or health guidelines). Violations: America's Health Rankings analysis of EPA SDWIS/ECHO 2024 data — average health-based violations per community water system (U.S. average: 2.5).
| # | State | Quality score /100 | Health-based violations per system |
|---|---|---|---|
| 1 | Hawaii | 99.9/100 | 0.0 |
| 2 | North Carolina | 99.7/100 | 1.9 |
| 3 | New Hampshire | 99.5/100 | 1.5 |
| 4 | Louisiana | 98.9/100 | 4.0 |
| 5 | Alaska | 97.7/100 | 2.6 |
| 6 | South Dakota | 96.5/100 | 1.1 |
| 7 | New Mexico | 95.9/100 | 3.6 |
| 8 | Indiana | 95.2/100 | 2.0 |
| 9 | Oregon | 90.5/100 | 1.8 |
| 10 | Vermont | 88.2/100 | 1.8 |
| 11 | Tennessee | 87.6/100 | 1.8 |
| 12 | Massachusetts | 87.3/100 | 1.5 |
| 13 | Colorado | 86.7/100 | 2.2 |
| 14 | Rhode Island | 85.8/100 | 5.5 |
| 15 | Maine | 85.6/100 | 1.9 |
| 16 | Washington | 85.6/100 | 1.8 |
| 17 | Maryland | 85.4/100 | 1.8 |
| 18 | Washington D.C. | 85.0/100 | 2.0 |
| 19 | Georgia | 84.8/100 | 2.3 |
| 20 | Mississippi | 84.6/100 | 1.8 |
| 21 | Wyoming | 84.3/100 | 1.7 |
| 22 | Alabama | 84.1/100 | 2.2 |
| 23 | North Dakota | 84.0/100 | 1.2 |
| 24 | Arkansas | 83.7/100 | 4.1 |
| 25 | California | 83.7/100 | 2.3 |
| 26 | South Carolina | 83.4/100 | 1.9 |
| 27 | Michigan | 83.1/100 | 1.4 |
| 28 | New York | 83.1/100 | 1.9 |
| 29 | Virginia | 83.0/100 | 2.1 |
| 30 | Montana | 82.4/100 | 1.9 |
| 31 | West Virginia | 82.3/100 | 3.0 |
| 32 | Idaho | 81.7/100 | 2.6 |
| 33 | Iowa | 81.7/100 | 1.5 |
| 34 | Delaware | 81.3/100 | 1.0 |
| 35 | Nebraska | 81.3/100 | 1.8 |
| 36 | Ohio | 81.0/100 | 1.3 |
| 37 | Florida | 80.6/100 | 2.0 |
| 38 | Kentucky | 80.5/100 | 2.3 |
| 39 | Connecticut | 80.1/100 | 1.4 |
| 40 | New Jersey | 79.8/100 | 1.5 |
| 41 | Minnesota | 78.8/100 | 2.4 |
| 42 | Texas | 78.1/100 | 2.6 |
| 43 | Wisconsin | 77.7/100 | 1.4 |
| 44 | Arizona | 77.4/100 | 2.1 |
| 45 | Utah | 77.3/100 | 2.2 |
| 46 | Illinois | 76.8/100 | 1.9 |
| 47 | Missouri | 76.2/100 | 1.8 |
| 48 | Kansas | 76.1/100 | 2.1 |
| 49 | Nevada | 76.1/100 | 4.2 |
| 50 | Pennsylvania | 75.9/100 | 1.6 |
| 51 | Oklahoma | 72.6/100 | 3.5 |
Averages describe states, not your faucet. A certified home water test screens for lead, nitrates, bacteria and dozens of other contaminants — the same categories EPA regulates.
Test your water at homeWe may earn a commission if you request quotes through this link. It costs you nothing and never affects the data we publish.
What a health-based violation actually means
EPA sets legal limits on more than 90 contaminants — bacteria, nitrates, lead action levels, disinfection byproducts and, since 2024, PFAS. A health-based violation means a water system exceeded one of those limits or failed a required treatment step. In 2023, about 4% of U.S. public water systems had at least one, and 92% of Americans were served by systems with none — but the remaining share is concentrated in specific states and, usually, in small rural systems.
State score and per-system violations can tell different stories: a state where most people are on one big clean utility can score well even if many tiny systems struggle, which is why we show both numbers. Wherever you live, your utility's annual Consumer Confidence Report — and a home test if you're on a well — is the ground truth for your own tap.