Moderate-low record-based concern — Population-weighted indicator 72/100
State Overview
Water quality across Arizona receives an overall grade of B (Moderate-low record-based concern) with an average score of 72 out of 100, based on EPA compliance data from 272 ZIP codes statewide. This is roughly in line with the national average of 75. Approximately 17% of ZIP codes (45 areas) receive a D or F grade, indicating communities with notable water quality concerns that warrant attention. The lowest-scoring area is ZIP code 86429 (Bullhead City) with a score of 29/100. 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