TapSafetyReport

About TapSafetyReport

TapSafetyReport provides free, science-based tap water quality reports for every US city. We believe everyone deserves to know what's in their water — presented clearly, without fear-mongering.

Data Sources

All water quality data comes from the EPA's Safe Drinking Water Information System (SDWIS), updated quarterly through the ECHO database. This includes:

  • Contaminant monitoring results for 90+ regulated contaminants
  • EPA violation records (health-based and non-health violations)
  • Water system information (population served, water source type)
  • Geographic service area mapping (cities and counties served)

Scoring Methodology

Each water system receives a score from 0 to 100, converted to a letter grade (A through F). The scoring algorithm considers:

Score Calculation

  • -8 ptsFor each contaminant exceeding EPA Maximum Contaminant Level (MCL)
  • -3 ptsFor each contaminant exceeding EPA Maximum Contaminant Level Goal (MCLG)
  • -5 ptsFor each health-based EPA violation
  • -1 ptFor each non-health EPA violation
  • +5 ptsBonus for a clean violation record

Grade Thresholds

A
80–100
B
60–79
C
40–59
D
20–39
F
0–19

State scores are population-weighted averages of all city scores within the state. This means larger cities have more influence on the state score, reflecting the water quality experienced by the majority of residents.

What We Are & Aren't

  • ✓A transparent, data-driven resource for understanding your water quality
  • ✓Based entirely on official EPA data, not proprietary testing
  • ✗Not a substitute for professional water testing
  • ✗Not affiliated with the EPA or any government agency

Last updated: 2026. Data refresh schedule: quarterly (aligned with EPA SDWIS updates).