Lower record-based concern — Population-weighted indicator 88/100
State Overview
Water quality across Michigan receives an overall grade of A (Lower record-based concern) with an average score of 88 out of 100, based on EPA compliance data from 699 ZIP codes statewide. This places Michigan 13 points above the national average of 75, indicating relatively strong water quality management across the state. A majority of ZIP codes (63%) earn an A grade, reflecting strong compliance across most water systems. The lowest-scoring area is ZIP code 49847 (Hermansville) with a score of 26/100. Scores are calculated from EPA Safe Drinking Water Information System (SDWIS) violation records, lead and copper testing results, PFAS monitoring data from UCMR5, and enforcement actions over the past 5 years.
Lowest Scoring ZIP Codes