Mixed record-based signals — Population-weighted indicator 68/100
State Overview
Water quality across Colorado receives an overall grade of C (Mixed record-based signals) with an average score of 68 out of 100, based on EPA compliance data from 291 ZIP codes statewide. This is 7 points below the national average of 75, suggesting significant water quality challenges that affect residents statewide. Approximately 1% of ZIP codes (4 areas) receive a D or F grade, indicating communities with notable water quality concerns that warrant attention. The lowest-scoring area is ZIP code 80261 (Denver) with a score of 45/100. 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