CITY REPORT HI

Mililani, HI Home Safety: Home Safety 100/100

1 ZIP code · 2 water systems · Updated

ZipCheckup grade for Mililani: A.

No federal data flags a major home-safety concern for this ZIP.

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

How Mililani Compares

Mililani100/100
Hawaii avg100/100
National avg73/100

Data: EPA SDWIS

1
ZIP Codes
2
Water Systems
0
ZIPs with Violations
A · 100
Avg Safety Score
Zone 3
Radon Risk (Low)
$871K
Median Home Value
$1,200
Est. Remediation (0.1% of home value)

Key Facts for Mililani Residents

  • Homes built before 1986: 51% - older plumbing may contain lead solder.
  • Estimated remediation: $1,200 per household.
  • CDC health risk index: 10.63.

Mililani's Water Providers

In Mililani, HI, residential water supply is distributed across multiple utilities rather than concentrated in one. The 2 leading providers out of 2 tracked systems each control their own infrastructure, file separate EPA compliance reports, and set independent rate schedules.

Overview

We track home safety data for 1 ZIP code in Mililani, Hawaii, covering 2 community water systems serving approximately 54,608 people. The EPA snapshots used for this build directly map water systems to 1 of 1 ZIP codes.

The available EPA record reports 0 violations for 1 ZIP code with a reported violation count.

Home Safety Score

Average Home Safety Score for Mililani: A (100/100)

Model 4.0.0 uses four measured components across three equally weighted domains. If a required domain is unavailable, no score is published:

Factor What It Measures
Water Quality EPA violations and compliance history
PFAS MCL Screen UCMR 5 testing against the covered federal MCLs
Radon Risk EPA radon zone classification
Annual AQI EPA AirData county-year median with at least 90 observed days

Water Sources

Mililani water systems draw from: Groundwater.

Lead & Copper

  • Average lead level (90th percentile): 0.0000 mg/L (EPA action level: 0.015 mg/L)
  • 0 of 1 ZIP code with known status exceed the EPA lead action level

Radon Risk

Dominant radon zone: Zone 3 (Low Risk)

Areas with No Violations

ZIP Code Safety Score System Population
96789 A Mililani 50,573

All ZIP Codes in Mililani

Data Sources

Reporting periods vary by source. Missing data is shown as unavailable, not as zero.

Mililani Community Health Snapshot

9.5%
Asthma (US: 9.8%)
12.4%
Diabetes (US: 10.4%)
14.2%
Poor Mental Health (US: 14.8%)

Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.

Compared to National Average

Asthma 9.5% ↓
Diabetes 12.4% ↑
Mental Health 14.2% ↓

Vertical line = national average. Above national · Below national

Mililani Infrastructure Age

1984
Median Build Year
51%
Built Before 1986
3%
Built Before 1970
Copper
Likely Pipe Material

With 51% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.

Source: U.S. Census Bureau American Community Survey (ACS).

Housing Age Profile

Reading the housing age data for Mililani - median build year 1984 - the overriding implication is that the plumbing materials inside a typical home here reflect pre-1986 construction standards. In practical terms, that means lead-soldered copper joints are common across much of the housing stock. Where those materials are present, water can leach lead as it moves through joints - a pathway that corrosion control treatment under federal rules is designed to reduce, though it cannot eliminate lead risk where the plumbing materials themselves contain lead.

1984
Median Year Built
51%
Pre-1986 (Lead Paint Risk)
3%
Pre-1970 (Lead Pipes Risk)
Pre-1970 (3%) 1970–1986 (48%) Post-1986 (49%)

Over half of homes in Mililani were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.

Source: U.S. Census Bureau ACS B25034.

How Remediation Costs Compare in Mililani

Low proportionality - that's the Mililani picture when remediation costs are placed against typical home equity.

Median Home Value
$871,000
Est. Remediation
$1,200
Remediation as % of home value 0.1%

Remediation costs in Mililani are relatively low compared to home values. The $800–$1,800 estimated range is a small fraction of median property value. Home values are 20% above the Hawaii average.

Mililani: Lead Risk & Vulnerable Populations

51%
Homes Built Before 1986

Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.

Pulling a tap sample fills the gap that utility data cannot close, particularly here where 51% of housing dates from the pre-rule era and citywide monitoring sits at or above the regulatory mark in Mililani.

Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.

Mililani: NFIP Claim Records and Water-Quality Context

6
Total FEMA Flood Claims
$36,034
Avg Reported Sum With Payment Data
0%
A/V Share of Claim-Record ZIPs

Historical NFIP data for Mililani contains 6 flood insurance claims. Among claims with payment data, the average reported building, contents, and ICC component sum is $36,034. Among ZIP codes with claim records, 0% have an A- or V-family dominant rated zone recorded in those historical claims. This is not a complete current FEMA property-map inventory.

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. The <strong>$1,200</strong> remediation estimate shown here excludes flood insurance and is not derived from NFIP claim count.

Claim count does not establish current property risk. Check the exact address in FEMA's current map and obtain a property-specific insurance quote when relevant.

Source: historical FEMA National Flood Insurance Program (NFIP) claim records. No current FEMA property-map designation is asserted.

Frequently Asked Questions

What does the Home Safety Score mean for Mililani, HI?
Mililani has an average Home Safety Score of 100/100 (Grade A) under model 4.0.0. The score combines EPA SDWIS identity plus accepted ECHO SDWA lifecycle-based water compliance, the PFAS MCL screen, EPA radon zone, and annual EPA AQI, and is published only when all required domains are observed. The available EPA record reports no violations for ZIP codes with reported counts. Check individual ZIP code reports for component details.
How does Mililani compare to Hawaii average?
Mililani has an average Home Safety Score of 100/100, which is above the Hawaii state average of 100/100 for the same model series.
How many water systems serve Mililani?
Mililani is served by 2 public water systems across 1 ZIP code, serving approximately 54,608 people.
How much does it cost to fix water issues in Mililani?
Estimated remediation costs in Mililani average $1,200 per household, ranging from $800 to $1,800. Costs include filtration, pipe replacement, radon mitigation, and flood protection.
HomeCitiesHawaii → Mililani, HI

How to cite this page

APA ZipCheckup. (2026). Mililani, HI Home Safety: Home Safety 100/100. https://zipcheckup.com/cities/hi/mililani/
BibTeX
@misc{zipcheckup-cities-hi-mililani,
  author = {{ZipCheckup}},
  title  = {{Mililani, HI Home Safety: Home Safety 100/100}},
  year   = {2026},
  url    = {https://zipcheckup.com/cities/hi/mililani/}
}

Page version: August 2026.

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