Free Water Quality Reports
Instant water quality grades for 20,883 US ZIP codes. Powered by EPA data, PFAS monitoring, and violation records.
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National Overview
Each mapped ZIP receives an internal public-record indicator from A to F based on contaminant records, PFAS occurrence data, violation history, and enforcement actions. It is not an EPA safety grade.
Highest record-based indicators
Lowest record-based indicators
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Featured local reports
Start with these local reports, then enter your own ZIP code above to review the public water-system data available for your area.
US Water Score aggregates publicly available water quality data from the EPA's Safe Drinking Water Information System (SDWIS), the Unregulated Contaminant Monitoring Rule (UCMR5) for PFAS, and enforcement records. The current build uses a July 2026 SDWIS snapshot and January 2026 UCMR5 files.
Model 1.1.0: each active community water system starts at 100 and may receive four documented penalty groups: five-year violation count and severity (up to 45 points), the latest EPA ECHO lead and copper 90th-percentile result selected by sampling-period dates (up to 25 points), UCMR5 PFAS occurrence values compared with EPA numerical MCL values (up to 20 points), and five-year enforcement actions (up to 10 points). System scores are weighted by reported population for ZIP indicators. Read the complete formula and limitations. Letter grades are internal screening indicators, not EPA ratings or regulatory compliance determinations.
This site provides water quality information for educational purposes only. Data may not reflect current conditions. Always contact your local water utility or review your annual Consumer Confidence Report for the most up-to-date information. This is not medical or legal advice.