Hawaii drinking water quality
Hawaii has 135 active public water systems serving 1.5 million people. 14 of them, 10%, had at least one EPA violation in the past three years, 8 have an unresolved violation today, and 0 are designated serious violators by the EPA.
Active systems
135
in 4 counties
People served
1.5M
118 community systems serve 1.5M
Violations, past 3 years
14
10% of active systems
Serious violators
0
0 systems carry a health flag
Largest counties
All 4 countiesLargest community water systems
All 135 systems| System | Serves | Status |
|---|---|---|
| Hnl-Windward-Pearl Harbor Honolulu County |
631,389 | |
| Waipahu-Ewa-Waianae Honolulu County |
217,479 | |
| Wailuku Maui County |
74,511 | |
| Joint Base Pearl Harbor-Hickam Honolulu County |
65,230 | |
| Mililani Honolulu County |
50,573 | |
| Hilo Hawaii County |
39,477 | |
| Schofield Barracks Honolulu County |
37,920 | |
| Lihue-Kapaa Kauai County |
34,854 | |
| Makawao Maui County |
29,868 | |
| North Kona Hawaii County |
29,581 |
About the Hawaii data
Retrieved from EPA ECHO on Oct 11, 2026.