Good — Average Score 87/100
State Overview
Water quality across Iowa receives an overall grade of B (Good) with an average score of 87 out of 100, based on EPA compliance data from 837 ZIP codes statewide. This places Iowa 12 points above the national average of 75, indicating relatively strong water quality management across the state. A majority of ZIP codes (64%) earn an A grade, reflecting strong compliance across most water systems. The lowest-scoring area is ZIP code 52322 (Oxford) with a score of 38/100. 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