Interactive tool
Compare State Drinking Water
Put any two U.S. states side by side on SDWIS violation totals, violation rates, and UCMR5 PFAS detection, straight from EPA public records.
- 66
- States & territories
- 143,076
- Water systems covered
- 10,559,500
- Violations on record
According to EPA SDWIS and UCMR5 public extracts (data vintage 2026-05-15), every figure is an aggregate across public water systems in each state. Violation rate is systems with violations divided by total systems; PFAS rate is detections divided by UCMR5-tested systems. These are registry metrics, not tap-water safety scores. See methodology.
Choose states to compare
Need county-level detail? Use the county compare tool.
Popular state comparisons
Download the SDWIS/UCMR5 state landscape snapshot cited on this page: sdwis-state-landscape.csv (same CSV as /statistics, CC0).
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. State totals are summed from EPA SDWIS public water-system records in the PlainWater database; PFAS rates use UCMR5-tested systems only. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.