Data Sources
TapScore currently uses EPA ECHO's 2026 Q2 SDWA snapshot. The source archive was published July 9, 2026 and covers data through the second quarter of 2026.
EPA ECHO SDWA Download Summary
Official quarterly Safe Drinking Water Act bulk-download documentation.
EPA ECHO SDWA Bulk ZIP
Source archive used for the Q2 2026 refresh; EPA response headers dated July 9, 2026.
EPA SDWIS Federal Reporting
Background on SDWIS reporting and state submissions.
EPA National Primary Drinking Water Regulations
Current federal standards and contaminant information.
Processing record
The refresh selected 49,378 active Community Water Systems, retained 1,267,289 unique violation IDs for those systems, and removed 5,464,100 duplicate enforcement rows. The published directory excludes systems that lack a usable name or valid state mapping.