Arizona Water Quality
Drinking water data for all 15 counties.
Avg Water Score
28.6
State Grade
F
Counties with Data
15
of 15 total
All Arizona Counties
| County | Water Score |
|---|---|
| Maricopa County | 68.0 |
| Pima County | 53.4 |
| Graham County | 37.0 |
| Santa Cruz County | 34.5 |
| Apache County | 34.3 |
| Coconino County | 33.6 |
| Pinal County | 30.4 |
| Mohave County | 26.2 |
| Navajo County | 24.7 |
| Cochise County | 21.7 |
| Yavapai County | 18.6 |
| Gila County | 16.6 |
| Yuma County | 15.2 |
| La Paz County | 9.8 |
| Greenlee County | 5.2 |
Concerned about your water quality?
Berkey water filters remove contaminants at home.
Sponsored
Frequently Asked Questions
Which county in Arizona has the best water quality?
Maricopa County has the highest water quality score in Arizona at 68.0/100 (Grade: B), based on EPA SDWIS data.
Which county in Arizona has the most water violations?
Greenlee County has among the lowest water quality scores in Arizona at 5.2/100. See the individual county page for detailed violation history.
Is the tap water safe to drink in Arizona?
Arizona has an average water quality score of 28.6/100 based on EPA Safe Drinking Water Act compliance data. Individual county scores vary — check your specific county's page for detailed information.
What contaminants are found in Arizona water supplies?
Drinking water quality varies by county and water system. The EPA Safe Drinking Water Information System (SDWIS) tracks violations for contaminants like lead, nitrates, bacteria, and disinfection byproducts. See individual county pages for specific contaminant and violation history.
Data Source
Water quality data sourced from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.
Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.