Public water system · HI0000320

Active

Mililani Memorial Park

At a glance

Mililani Memorial Park (PWSID HI0000320) is an active non-transient non-community water system in Honolulu County, Hawaii. It reports serving 100 people through 1 service connection. Its primary water source is surface water, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in April 2022.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

100

Service connections

Primary source

Surface water

System type

NTNCWS

Non-transient non-community water system

System record

PWSIDHI0000320

System typeNon-transient non-community water system

Activity statusActive

Population served100

Service connections1

Primary water sourceSurface water

Owner typePrivate

Primacy agencyHI state drinking water program

City servedMililani Bws

StateHawaii

ZIP—

CountyHonolulu County

How does Mililani Memorial Park compare with other water systems in Honolulu County?

By EPA's size categories, Mililani Memorial Park is a very small system (500 people or fewer). Honolulu County has 38 active public water systems. Its population served is well below the county average of 29,687 people per system, and accounts for less than 0.1% of the 1,128,119 people reported by systems filed under the county. Across Hawaii, the 136 active systems average 11,181 people each. Nationally, the average active non-transient non-community water system reports serving 430 people, so Mililani Memorial Park is well below that figure.

What does “non-transient non-community water system” mean?

A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. Hawaii has 14 active non-transient non-community water systems, 10% of the state's 136 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 9 Hawaii systems (6.6%) list surface water as their primary source.

Who owns and regulates Mililani Memorial Park?

EPA lists Mililani Memorial Park as privately owned. The HI state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 16 of the 38 active systems in Honolulu County (42%) are also privately owned.

Does Mililani Memorial Park have drinking water violations?

Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in April 2022. The violations listed here began between January 2018 and April 2022. By type: 6 required treatment not met and 6 monitoring and reporting. The contaminant or rule involved most often is Surface Water Treatment Rule (11 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.

Began	Violation	Contaminant or rule	Health-based	Status
2022-04-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
2022-04-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2021-05-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2021-05-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
2020-12-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
2020-12-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2020-03-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2020-03-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
2020-02-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2020-02-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
2018-01-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Long Term 2 Enhanced Surface Water Treatment Rulecode 0800	No	Resolved
2018-01-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved

The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.

Mililani Memorial Park: frequently asked questions

Who runs Mililani Memorial Park?

Mililani Memorial Park (PWSID HI0000320) is a non-transient non-community water system privately owned. It is regulated by the HI state drinking water program.

How many people does Mililani Memorial Park serve?

Mililani Memorial Park reports serving 100 people through 1 service connection in Honolulu County, Hawaii.

Where does Mililani Memorial Park get its water?

EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.

Does Mililani Memorial Park have any drinking water violations?

Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in April 2022. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.

Is Mililani Memorial Park's water safe to drink?

AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in April 2022. For current results, consult EPA ECHO, or the HI state drinking water program.

Where can I find Mililani Memorial Park's water quality report?

The annual Consumer Confidence Report requirement applies to community water systems. Mililani Memorial Park is a non-transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.

Other water systems in Honolulu County

Water system	County	Population served	Type	Source
Hnl-Windward-Pearl Harbor	Honolulu	631,389	Community	Groundwater
Waipahu-Ewa-Waianae	Honolulu	217,479	Community	Groundwater
Joint Base Pearl Harbor-Hickam	Honolulu	65,230	Community	Groundwater
Mililani	Honolulu	50,573	Community	Groundwater
Schofield Barracks	Honolulu	37,920	Community	Groundwater
Wahiawa	Honolulu	23,348	Community	Groundwater

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About this data

Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.

Cite as: AquaCensus, “Mililani Memorial Park, PWSID HI0000320, Hawaii”, https://aquacensus.com/water-systems/hawaii/mililani-memorial-park-hi0000320 (data as of October 1, 2026).