Mixed record-based signals — Population-weighted indicator 64/100
State Overview
Water quality across Illinois receives an overall grade of C (Mixed record-based signals) with an average score of 64 out of 100, based on EPA compliance data from 883 ZIP codes statewide. This is 11 points below the national average of 75, suggesting significant water quality challenges that affect residents statewide. Approximately 2% of ZIP codes (21 areas) receive a D or F grade, indicating communities with notable water quality concerns that warrant attention. The lowest-scoring area is ZIP code 61752 (Le Roy) with a score of 35/100. 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
Highest Scoring ZIP Codes