Clean, safe drinking water is something most Americans take for granted. But water quality varies significantly from county to county. Using EPA Safe Drinking Water Information System (SDWIS) data, we identified the 25 counties with the best water quality scores in the nation.
These counties have strong compliance records, minimal health-based violations, and reliable water infrastructure that consistently meets or exceeds federal standards.
The 25 Counties with the Best Water Quality
Autauga County, Alabama leads with a water quality score of 86. These counties have the best drinking water quality in America:
| Rank | County | State | Score | Grade | Health Violations | Violation Rate |
|---|---|---|---|---|---|---|
| 1 | Autauga County, Alabama | AL | 86 | B | 0 | 0.00 |
| 2 | Bullock County, Alabama | AL | 86 | B | 0 | 0.00 |
| 3 | Chambers County, Alabama | AL | 86 | B | 0 | 0.00 |
| 4 | Cherokee County, Alabama | AL | 86 | B | 0 | 0.00 |
| 5 | Chilton County, Alabama | AL | 86 | B | 0 | 0.00 |
| 6 | Cleburne County, Alabama | AL | 86 | B | 0 | 0.00 |
| 7 | Covington County, Alabama | AL | 86 | B | 0 | 0.00 |
| 8 | Crenshaw County, Alabama | AL | 86 | B | 0 | 0.00 |
| 9 | Cullman County, Alabama | AL | 86 | B | 0 | 0.00 |
| 10 | Dallas County, Alabama | AL | 86 | B | 0 | 0.00 |
| 11 | DeKalb County, Alabama | AL | 86 | B | 0 | 0.00 |
| 12 | Franklin County, Alabama | AL | 86 | B | 0 | 0.00 |
| 13 | Geneva County, Alabama | AL | 86 | B | 0 | 0.00 |
| 14 | Greene County, Alabama | AL | 86 | B | 0 | 0.00 |
| 15 | Hale County, Alabama | AL | 86 | B | 0 | 0.00 |
| 16 | Henry County, Alabama | AL | 86 | B | 0 | 0.00 |
| 17 | Lamar County, Alabama | AL | 86 | B | 0 | 0.00 |
| 18 | Lawrence County, Alabama | AL | 86 | B | 0 | 0.00 |
| 19 | Limestone County, Alabama | AL | 86 | B | 0 | 0.00 |
| 20 | Lowndes County, Alabama | AL | 86 | B | 0 | 0.00 |
| 21 | Macon County, Alabama | AL | 86 | B | 0 | 0.00 |
| 22 | Madison County, Alabama | AL | 86 | B | 0 | 0.00 |
| 23 | Montgomery County, Alabama | AL | 86 | B | 0 | 0.00 |
| 24 | Morgan County, Alabama | AL | 86 | B | 0 | 0.00 |
| 25 | Perry County, Alabama | AL | 86 | B | 0 | 0.00 |
Where the Best Water Quality Counties Are Located
The best water quality counties cluster in specific regions. Alabama (25 counties) are most represented among the top 25. Many of these counties benefit from protected groundwater sources, newer infrastructure, and strong state oversight.
Methodology
Water quality scores are calculated using EPA SDWIS data with percentile-rank methodology. Health-based violations carry the most weight, followed by monitoring and treatment technique violations. Letter grades map to score ranges: A (90-100), B (75-89), C (60-74), D (40-59), F (0-39). Counties are ranked by water score in descending order.
Data source: U.S. Environmental Protection Agency, Safe Drinking Water Information System (SDWIS) Federal Reporting Services, accessed via ECHO API. All figures are estimates based on publicly available compliance data and may differ from other published analyses due to methodology differences.