C

Fair — Average Score 65/100

Water Quality in Colorado

461 ZIP codes analyzed · Data updated March 2026

State Overview

About Water Quality in Colorado

Water quality across Colorado receives an overall grade of C (Fair) with an average score of 65 out of 100, based on EPA compliance data from 461 ZIP codes statewide. This is 10 points below the national average of 75, suggesting significant water quality challenges that affect residents statewide. Approximately 26% of ZIP codes (120 areas) receive a D or F grade, indicating communities with notable water quality concerns that warrant attention. The lowest-scoring area is ZIP code 81069 (Rye) with a score of 27/100. 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.

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All 461 ZIP Codes in Colorado

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