Hawaii tap water
0 of 44 Hawaii water systems with full PFAS testing (0%) averaged above a 2024 federal PFAS level at one or more sampling points.
- 118 active community water systems in the EPA file; 42 serve 3,300+ people and have a full PFAS set.
- 2 systems had at least one health-based violation since 2021-10-26.
- 0 systems report a lead 90th percentile above 15 ppb (some results are old; check each system page).
Largest systems
| System | People served | PFAS above a 2024 level? | Health-based violations since 2021-10-26 |
|---|---|---|---|
| Hnl-Windward-Pearl Harbor | 631,389 | No | 0 |
| Waipahu-Ewa-Waianae | 217,479 | No | 0 |
| Wailuku | 74,511 | No | 0 |
| Joint Base Pearl Harbor-Hickam | 65,230 | No | 0 |
| Mililani | 50,573 | No | 0 |
| Hilo | 39,477 | No | 0 |
| Schofield Barracks | 37,920 | No | 0 |
| Lihue-Kapaa | 34,854 | No | 0 |
Counties
All 5 utilities with a page in Hawaii
- Hnl-Windward-Pearl Harbor 631,389
- Joint Base Pearl Harbor-Hickam 65,230
- Mililani 50,573
- Wailuku 74,511
- Waipahu-Ewa-Waianae 217,479
Why not "the state's water quality"? You drink from one utility, not a state. Rollups count systems, not people, so one large utility counts the same as a small one. Use the system pages for your actual water.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.