Hawaii Water Quality
Drinking water data for all 5 counties.
Avg Water Score
78.6
State Grade
B
Counties with Data
4
of 5 total
All Hawaii Counties
| County | Water Score |
|---|---|
| Kauai County | 86.0 |
| Maui County | 86.0 |
| Honolulu County | 71.9 |
| Hawaii County | 70.6 |
| Kalawao County | — |
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Frequently Asked Questions
Which county in Hawaii has the best water quality?
Kauai County has the highest water quality score in Hawaii at 86.0/100 (Grade: A), based on EPA SDWIS data.
Which county in Hawaii has the most water violations?
Hawaii County has among the lowest water quality scores in Hawaii at 70.6/100. See the individual county page for detailed violation history.
Is the tap water safe to drink in Hawaii?
Hawaii has an average water quality score of 78.6/100 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 Hawaii 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.