Public water system · HI0000370

Active

Palehua Solar Observatory

At a glance

Palehua Solar Observatory (PWSID HI0000370) is an active non-transient non-community water system in Honolulu County, Hawaii. It reports serving 50 people through 10 service connections. Its primary water source is purchased groundwater, and EPA lists it as owned by the federal government. EPA's records list 8 violations for this system; 3 are health-based, and the most recent began in January 2009.

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

Population served

Service connections

Primary source

GWP

Purchased groundwater

System type

NTNCWS

Non-transient non-community water system

System record

PWSIDHI0000370

System typeNon-transient non-community water system

Activity statusActive

Population served50

Service connections10

Primary water sourcePurchased groundwater

Owner typeFederal government

Primacy agencyHI state drinking water program

City servedMakakilo

StateHawaii

ZIP—

CountyHonolulu County

How does Palehua Solar Observatory compare with other water systems in Honolulu County?

By EPA's size categories, Palehua Solar Observatory 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 Palehua Solar Observatory 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. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own. 14 Hawaii systems (10%) list purchased groundwater as their primary source.

Who owns and regulates Palehua Solar Observatory?

EPA lists Palehua Solar Observatory as owned by the federal government. 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. 11 of the 38 active systems in Honolulu County (29%) are also owned by the federal government.

Does Palehua Solar Observatory have drinking water violations?

EPA's records list 8 violations for this system; 3 are health-based, and the most recent began in January 2009. The violations listed here began between November 1996 and January 2009. By type: 5 monitoring and reporting and 3 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (6 of them). EPA lists 5 as archived and 3 as resolved. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status. 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
2009-01-01	Monitoring and reportingMonitoring, Routine Major (TCR) · code 23	Total coliform bacteria (TCR)code 3100	No	Resolved
2008-07-01	Monitoring and reportingWater Quality Parameter M/R · code 53	Lead and Copper Rulecode 5000	No	Resolved
2007-03-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22	Total coliform bacteria (TCR)code 3100	Yes	Archived
2007-03-01	Monitoring and reportingMonitoring, Routine Major (TCR) · code 23	Total coliform bacteria (TCR)code 3100	No	Archived
2004-10-01	Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24	Total coliform bacteria (TCR)code 3100	No	Archived
2003-01-01	Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52	Lead and Copper Rulecode 5000	No	Resolved
1996-11-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22	Total coliform bacteria (TCR)code 3100	Yes	Archived
1996-11-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21	Total coliform bacteria (TCR)code 3100	Yes	Archived

All 8 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.

Palehua Solar Observatory: frequently asked questions

Who runs Palehua Solar Observatory?

Palehua Solar Observatory (PWSID HI0000370) is a non-transient non-community water system owned by the federal government. It is regulated by the HI state drinking water program.

How many people does Palehua Solar Observatory serve?

Palehua Solar Observatory reports serving 50 people through 10 service connections in Honolulu County, Hawaii.

Where does Palehua Solar Observatory get its water?

EPA SDWIS lists this system's primary water source as purchased groundwater. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own.

Does Palehua Solar Observatory have any drinking water violations?

EPA's records list 8 violations for this system; 3 are health-based, and the most recent began in January 2009. 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 Palehua Solar Observatory'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. EPA's records list 8 violations for this system; 3 are health-based, and the most recent began in January 2009. For current results, consult EPA ECHO, or the HI state drinking water program.

Where can I find Palehua Solar Observatory's water quality report?

The annual Consumer Confidence Report requirement applies to community water systems. Palehua Solar Observatory 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, “Palehua Solar Observatory, PWSID HI0000370, Hawaii”, https://aquacensus.com/water-systems/hawaii/palehua-solar-observatory-hi0000370 (data as of October 1, 2026).