Data: EPA SDWIS, NWS, State plumbing boards, Rewiring America Last verified: 2026-06-03

Throughout Hawaii, public water systems report above-baseline compliance with federal drinking water standards — violations exist but are isolated rather than systemic.

Score Distribution

How Hawaii's 137 ZIP codes are distributed across safety grades.

Top 10 Safest ZIP Codes in Hawaii

Highest Home Safety Scores in the state.

10 Lowest-Scoring ZIP Codes in Hawaii

County Rankings

Water quality breakdown by county. 5 counties with data in Hawaii.

Most Common Contaminants in Hawaii

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Overview

We track water quality, weather alerts, plumbing regulations, and energy rebates for 137 ZIP codes across Hawaii, covering 89 community water systems that serve approximately 1,274,618 people.

9 of 137 ZIP codes (7%) have recorded EPA violations. 1 health-based violations have been documented.

Plumbing Regulations

Hawaii follows the Uniform Plumbing Code (2018 edition).

• Plumbing code: UPC (2018)
• Homeowner DIY: Licensed plumber required
• Water heater permit: Required
• Annual backflow test: Required
• Seismic strapping: Required

Full Hawaii regulations →

Areas with Most Violations

Areas with No Violations

Home Safety Score

Average Home Safety Score for Hawaii: B (79/100)

Lead & Copper

• Average lead level (90th percentile): 0.0072 mg/L (EPA action level: 0.015 mg/L)
• 3 ZIP codes exceed the EPA lead action level

Radon Risk

• High risk (Zone 1): 0 ZIP codes (0%)
• Moderate risk (Zone 2): 0 ZIP codes
• Low risk (Zone 3): 137 ZIP codes

ZIP Code Reports for Hawaii

Largest Communities

Lowest Safety Scores

Highest Safety Scores

All 137 ZIP Codes in Hawaii

• 96701 (Aiea) [B]
• 96703 (Anahola) [B]
• 96861 (Camp H M Smith) [C]
• 96704 (Captain Cook) [B]
• 96705 (Eleele) [C]
• 96706 (Ewa Beach) [C]
• 96858 (Fort Shafter) [C]
• 96708 (Haiku) [B]
• 96710 (Hakalau) [C]
• 96712 (Haleiwa) [C]
• 96713 (Hana) [A]
• 96714 (Hanalei) [B]
• 96715 (Hanamaulu) [C]
• 96716 (Hanapepe) [C]
• 96717 (Hauula) [C]
• 96718 (Hawaii National Park) [A]
• 96719 (Hawi) [C]
• 96720 (Hilo) [B] — 2 violations
• 96721 (Hilo) [A] — 2 violations
• 96725 (Holualoa) [A] — 1 violation ⚠
• 96726 (Honaunau) [C]
• 96727 (Honokaa) [B]
• 96801 (Honolulu) [A]
• 96802 (Honolulu) [A]
• 96803 (Honolulu) [A]
• 96804 (Honolulu) [A]
• 96805 (Honolulu) [A]
• 96806 (Honolulu) [A]
• 96807 (Honolulu) [A]
• 96808 (Honolulu) [A]
• 96809 (Honolulu) [A]
• 96810 (Honolulu) [A]
• 96811 (Honolulu) [A]
• 96812 (Honolulu) [A]
• 96813 (Honolulu) [B]
• 96814 (Honolulu) [A]
• 96815 (Honolulu) [B]
• 96816 (Honolulu) [B]
• 96817 (Honolulu) [B]
• 96818 (Honolulu) [A]
• 96819 (Honolulu) [B]
• 96820 (Honolulu) [A]
• 96821 (Honolulu) [B]
• 96822 (Honolulu) [B]
• 96823 (Honolulu) [A]
• 96824 (Honolulu) [A]
• 96825 (Honolulu) [B]
• 96826 (Honolulu) [B]
• 96828 (Honolulu) [A]
• 96830 (Honolulu) [A]
• 96836 (Honolulu) [A]
• 96837 (Honolulu) [A]
• 96838 (Honolulu) [A]
• 96839 (Honolulu) [A]
• 96840 (Honolulu) [A]
• 96841 (Honolulu) [A]
• 96843 (Honolulu) [A]
• 96844 (Honolulu) [A]
• 96846 (Honolulu) [A]
• 96847 (Honolulu) [A]
• 96848 (Honolulu) [A]
• 96849 (Honolulu) [A]
• 96850 (Honolulu) [A]
• 96728 (Honomu) [A]
• 96729 (Hoolehua) [A]
• 96853 (J B P H H) [C]
• 96860 (J B P H H) [C]
• 96730 (Kaaawa) [C]
• 96731 (Kahuku) [A]
• 96732 (Kahului) [C]
• 96733 (Kahului) [B]
• 96734 (Kailua) [C]
• 96740 (Kailua Kona) [B]
• 96745 (Kailua Kona) [B]
• 96741 (Kalaheo) [A]
• 96742 (Kalaupapa) [A] — 1 violation
• 96743 (Kamuela) [B]
• 96744 (Kaneohe) [B] — 3 violations
• 96746 (Kapaa) [C]
• 96755 (Kapaau) [C]
• 96707 (Kapolei) [B]
• 96709 (Kapolei) [C]
• 96747 (Kaumakani) [A]
• 96748 (Kaunakakai) [A]
• 96749 (Keaau) [B]
• 96750 (Kealakekua) [B]
• 96751 (Kealia) [A]
• 96739 (Keauhou) [C]
• 96752 (Kekaha) [B]
• 96753 (Kihei) [B]
• 96754 (Kilauea) [B]
• 96756 (Koloa) [B]
• 96757 (Kualapuu) [A] — 1 violation
• 96790 (Kula) [A]
• 96759 (Kunia) [A]
• 96760 (Kurtistown) [B]
• 96761 (Lahaina) [A]
• 96767 (Lahaina) [A]
• 96762 (Laie) [B]
• 96763 (Lanai City) [A] — 1 violation
• 96764 (Laupahoehoe) [A]
• 96765 (Lawai) [B]
• 96766 (Lihue) [B]
• 96863 (M C B H Kaneohe Bay) [C]
• 96768 (Makawao) [A]
• 96769 (Makaweli) [B]
• 96770 (Maunaloa) [B] — 4 violations
• 96789 (Mililani) [B]
• 96771 (Mountain View) [B]
• 96772 (Naalehu) [C]
• 96773 (Ninole) [A]
• 96737 (Ocean View) [C]
• 96774 (Ookala) [A]
• 96776 (Paauilo) [A]
• 96777 (Pahala) [A]
• 96778 (Pahoa) [B]
• 96779 (Paia) [B]
• 96780 (Papaaloa) [B]
• 96781 (Papaikou) [A]
• 96782 (Pearl City) [B]
• 96783 (Pepeekeo) [A]
• 96722 (Princeville) [B]
• 96788 (Pukalani) [A]
• 96784 (Puunene) [A]
• 96857 (Schofield Barracks) [A] — 1 violation
• 96859 (Tripler Army Medical Center) [C]
• 96785 (Volcano) [C]
• 96786 (Wahiawa) [A]
• 96791 (Waialua) [C]
• 96792 (Waianae) [C]
• 96738 (Waikoloa) [A]
• 96793 (Wailuku) [A]
• 96795 (Waimanalo) [C]
• 96796 (Waimea) [C]
• 96797 (Waipahu) [A]
• 96898 (Wake Island) [C]
• 96854 (Wheeler Army Airfield) [C]

Data Sources

• Water quality: EPA Safe Drinking Water Information System (SDWIS)
• Regulations: State plumbing boards, ICC, IAPMO

Updated daily.

Frequently Asked Questions

Is the water safe to drink in Hawaii?

Hawaii has 89 community water systems serving 1,274,618 people across 137 ZIP codes. There are 16 recorded violations, including 1 health-based. 9 of 137 ZIP codes have at least one violation.

What plumbing code does Hawaii follow?

Hawaii follows the UPC plumbing code. A licensed plumber is generally required for plumbing work.

Is lead a concern in Hawaii's drinking water?

3 ZIP codes in Hawaii have lead levels exceeding the EPA action level of 0.015 mg/L.