Find the Cleanest Water
for Your Next Home
Comprehensive drinking water rankings based on EPA SDWIS data. Discover accurate Water Quality Scores for 179+ US cities and 187 public water systems.
50
States
179
Cities
187
Water Systems
86
Avg Score
Best States for Water Quality
View All →Best Cities for Water Quality
View All → 1
San Jose
CA · Santa Clara County
100 A
2
San Francisco
CA · San Francisco County
100 A
3
Oakland
CA · Alameda County
100 A
4
Bakersfield
CA · Kern County
100 A
5
Houston
TX · Harris County
100 A
6
Austin
TX · Travis County
100 A
7
Corpus Christi
TX · Nueces County
100 A
8
Buffalo
NY · Erie County
100 A
9
Rochester
NY · Monroe County
100 A
10
Tallahassee
FL · Leon County
100 A
Recent Violations
| Violation | Severity | Date | Status |
|---|---|---|---|
| Treatment Technique Violation NH1361011 | minor | 2025-10-19 | unresolved |
| Treatment Technique Violation TX0710001 | critical | 2025-10-09 | resolved |
| Inorganic Chemicals Violation MA3349000 | critical | 2025-09-28 | resolved |
| Maximum Residual Disinfectant Level NC0392011 | critical | 2025-08-09 | resolved |
| Maximum Contaminant Level Violation LA1170001 | major | 2025-08-07 | pending |
Common Contaminants
View All →Lead
inorganicDevelopmental delays in children, kidney problems, high blood pressure in adults
EPA MCL: 15 μg/L
Arsenic
inorganicSkin damage, circulatory system problems, increased risk of cancer
EPA MCL: 10 μg/L
PFAS (Per- and Polyfluoroalkyl Substances)
organicDevelopmental effects, liver damage, immune system effects, increased cancer risk
EPA MCL: 0.004 μg/L
PFOA (Perfluorooctanoic Acid)
organicCancer risk, liver damage, developmental effects
EPA MCL: 0.004 μg/L
PFOS (Perfluorooctane Sulfonate)
organicCancer risk, thyroid effects, immune system effects
EPA MCL: 0.004 μg/L
Nitrate
inorganicBlue baby syndrome in infants, decreased oxygen-carrying capacity of blood
EPA MCL: 10 mg/L
Explore Water Quality Data
Browse by state, city, or contaminant. Every data point is sourced from EPA's Safe Drinking Water Information System.