Water quality · Hawaii
Water quality in Hawaii
Of the 5 Hawaii ZIPs matched to an EPA SDWIS community water system, none reports a health-based violation in the last 3 years. SDWIS reports the system serving the county, never an address-level test, and never private wells.
Last verified 2026-09-24 · methodology
Water quality by ZIP code in Hawaii
The largest community water system EPA lists for each ZIP's county, and its health-based violations in the last 3 years.
| ZIP | Largest system | Health-based violations |
|---|---|---|
| 96813HonoluluHonolulu County | HNL-WINDWARD-PEARL HARBOR | None |
| 96732KahuluiMaui County | WAILUKU | None |
| 96720HiloHawaii County | HILO | None |
| 96766Lihue (Kauai)Kauai County | LIHUE-KAPAA | None |
| 96793Wailuku (Maui)Maui County | WAILUKU | None |
County-level figures from EPA SDWIS, joined to each ZIP by county. None of them is a measurement at a specific address.
What lands here
Pages show the largest community water system on record for the ZIP's county, its PWSID and population served, and its health-based and total violations in the last 3 years. Lead and copper sampling results are not shown; your utility's annual water quality report (CCR) has them.
Source & refresh
EPA SDWIS. Refreshed quarterly (federal mandate). Primary source →
Hawaii top concern
Tsunami, lava-zone, water-source isolation
Hawaii's federated data is unusual: FEMA tsunami evacuation zones are state-managed alongside NFHL flood maps; Big Island lava-flow zones (USGS) overlay FEMA hazard layers. Each island operates independent water utilities, so EPA SDWIS PWSIDs do not aggregate across the state.
See Hawaii state page for the full state-level rollup across all 12 dimensions.
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EPA Radon Zones — what 1, 2, and 3 mean and when you should test
EPA classifies every US county into Zone 1 (high), Zone 2 (moderate), or Zone 3 (low) for radon. Plain-English guide to the classifications and at-home testing.
EPA AQI categories explained — what 0–50 Good through 301–500 Hazardous mean
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Lead and Copper Rule 2024 — the federal lead-pipe inventory mandate
The 2024 Lead and Copper Rule Revisions (LCRR) require every US community water system to inventory and report lead service lines. Plain-English guide.