Good — Average Score 77/100
State Overview
Water quality across New Hampshire receives an overall grade of B (Good) with an average score of 77 out of 100, based on EPA compliance data from 184 ZIP codes statewide. This is roughly in line with the national average of 75. Approximately 17% of ZIP codes (32 areas) receive a D or F grade, indicating communities with notable water quality concerns that warrant attention. The lowest-scoring area is ZIP code 03885 (Stratham) with a score of 18/100. 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