Public water system · HI0000368
ActiveWaiahole
At a glance
Waiahole (PWSID HI0000368) is an active community water system in Honolulu County, Hawaii. It reports serving 300 people through 112 service connections. Its primary water source is groundwater, and EPA lists it as owned by a state government. EPA's records list 3 violations for this system; 1 is health-based, and the most recent began in February 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
300
Service connections
112
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Waiahole compare with other water systems in Honolulu County?
By EPA's size categories, Waiahole 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 community water system reports serving 6,703 people, so Waiahole is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Hawaii has 119 active community water systems, 88% of the state's 136 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 112 Hawaii systems (82%) list groundwater as their primary source.
Who owns and regulates Waiahole?
EPA lists Waiahole as owned by a state 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. 3 of the 38 active systems in Honolulu County (7.9%) are also owned by a state government.
Does Waiahole have drinking water violations?
EPA's records list 3 violations for this system; 1 is health-based, and the most recent began in February 2020. The violations listed here began between January 2000 and February 2020. By type: 2 monitoring and reporting and 1 contaminant level above the legal limit. The contaminants or rules involved are E. coli, Revised Total Coliform Rule and Gross alpha (excluding radon and uranium). EPA lists 2 as resolved and 1 as archived. 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. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2020-02-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2020-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2000-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 3 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.
Waiahole: frequently asked questions
Who runs Waiahole?
Waiahole (PWSID HI0000368) is a community water system owned by a state government. It is regulated by the HI state drinking water program.
How many people does Waiahole serve?
Waiahole reports serving 300 people through 112 service connections in Honolulu County, Hawaii.
Where does Waiahole get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Waiahole have any drinking water violations?
EPA's records list 3 violations for this system; 1 is health-based, and the most recent began in February 2020. 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 Waiahole'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 3 violations for this system; 1 is health-based, and the most recent began in February 2020. For current results, consult the system's annual water quality report, EPA ECHO, or the HI state drinking water program.
Where can I find Waiahole's water quality report?
As a community water system, Waiahole must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
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, “Waiahole, PWSID HI0000368, Hawaii”, https://aquacensus.com/water-systems/hawaii/waiahole-hi0000368 (data as of October 1, 2026).