Tap water in Honolulu, HI scores well — low violation counts, above-average safety grade.

Data: EPA SDWIS Last verified: 2026-06-03

Water Quality Map: Honolulu, HI

Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.

A B C D F

Overview

We track water quality and home safety data for 41 ZIP codes in Honolulu, Hawaii (population ~415,471), covering 8 community water systems serving approximately 947,522 people region-wide.

No EPA violations recorded across any ZIP codes in Honolulu — an excellent indicator of water quality.

Home Safety Score

Average Home Safety Score for Honolulu: A (85/100)

The score combines three factors:

Factor	What It Measures
Water Quality	EPA violations and compliance history
Lead Levels	90th percentile lead concentration vs EPA action level
Radon Risk	EPA radon zone classification

Water Sources

Honolulu water systems draw from: Groundwater.

Lead & Copper

• Lead data: not yet available for Honolulu
• 0 ZIP codes exceed the EPA lead action level

Radon Risk

Dominant radon zone: Zone 3 (Low Risk)

• Zone 1 (High): 0 ZIP codes
• Zone 2 (Moderate): 0 ZIP codes
• Zone 3 (Low): 41 ZIP codes

Areas with No Violations

All ZIP Codes in Honolulu

• 96801 [A]
• 96802 [A]
• 96803 [A]
• 96804 [A]
• 96805 [A]
• 96806 [A]
• 96807 [A]
• 96808 [A]
• 96809 [A]
• 96810 [A]
• 96811 [A]
• 96812 [A]
• 96813 [B]
• 96814 [A]
• 96815 [B]
• 96816 [B]
• 96817 [B]
• 96818 [A]
• 96819 [B]
• 96820 [A]
• 96821 [B]
• 96822 [B]
• 96823 [A]
• 96824 [A]
• 96825 [B]
• 96826 [B]
• 96828 [A]
• 96830 [A]
• 96836 [A]
• 96837 [A]
• 96838 [A]
• 96839 [A]
• 96840 [A]
• 96841 [A]
• 96843 [A]
• 96844 [A]
• 96846 [A]
• 96847 [A]
• 96848 [A]
• 96849 [A]
• 96850 [A]

Data Sources

• Water quality: EPA Safe Drinking Water Information System (SDWIS)
• Lead/copper: EPA Lead and Copper Rule sampling data
• Radon: EPA Map of Radon Zones

Updated daily.

How Remediation Costs Compare in Honolulu

While no remediation project is entirely without cost, the relationship between estimated remediation and property values in Honolulu is notably favorable — the equity share is small enough that the household financial perspective is one of proportionality rather than pressure, and most homeowners can treat it as routine planning rather than a significant financial event.

Median Home Value

$930,000

Est. Remediation

$1,744

Remediation as % of home value 0.2%

Remediation costs in Honolulu are relatively low compared to home values. The $1,150–$2,606 estimated range is a small fraction of median property value. Home values are 28% above the Hawaii average.

Honolulu: Flood History & Water Damage Risk

Substantially more flood exposure than most communities appears in Honolulu's NFIP record — 1127 documented claims and 39% of ZIP codes in FEMA flood zones. That exposure level makes the water-quality implications of flooding an active planning consideration rather than a background one.

1,127

Total FEMA Flood Claims

$14,845

Avg Claim Payout

39%

ZIPs in FEMA Flood Zones

~56

Est. Claims/Year

Honolulu has a significant flood history with 1,127 FEMA flood insurance claims on record, averaging $14,845 per claim. With 39% of ZIP codes in FEMA-designated flood zones, flood risk is a major concern for homeowners and water quality.

How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,744</strong> remediation cost per household.

Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.

Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.