Public water system · HI0000203
ActiveKailua
At a glance
Kailua (PWSID HI0000203) is an active community water system in Maui County, Hawaii. It reports serving 90 people through 27 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 7 are health-based, and the most recent began in January 2018.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
90
Service connections
27
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Kailua compare with other water systems in Maui County?
By EPA's size categories, Kailua is a very small system (500 people or fewer). Maui County has 39 active public water systems. Its population served is well below the county average of 4,338 people per system, and accounts for less than 0.1% of the 169,182 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 Kailua 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 Kailua?
EPA lists Kailua 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. 22 of the 39 active systems in Maui County (56%) are also privately owned.
Does Kailua have drinking water violations?
Of the 12 most recent violations in EPA's records, 7 are health-based, and the most recent began in January 2018. The violations listed here began between April 1999 and January 2018. By type: 7 required treatment not met and 5 monitoring and reporting. The contaminant or rule involved most often is Surface Water Treatment Rule (7 of them). EPA lists 6 as resolved and 6 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 |
|---|---|---|---|---|
| 2018-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2010-01-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1999-10-01 | Required treatment not metFailure to Filter (SWTR) · code 42 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1999-09-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
| 1999-08-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
| 1999-07-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
| 1999-06-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
| 1999-05-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
| 1999-04-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Archived |
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.
Kailua: frequently asked questions
Who runs Kailua?
Kailua (PWSID HI0000203) is a community water system privately owned. It is regulated by the HI state drinking water program.
How many people does Kailua serve?
Kailua reports serving 90 people through 27 service connections in Maui County, Hawaii.
Where does Kailua 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 Kailua have any drinking water violations?
Of the 12 most recent violations in EPA's records, 7 are health-based, and the most recent began in January 2018. 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 Kailua'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, 7 are health-based, and the most recent began in January 2018. For current results, consult the system's annual water quality report, EPA ECHO, or the HI state drinking water program.
Where can I find Kailua's water quality report?
As a community water system, Kailua 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 Maui County
Related pages
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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, “Kailua, PWSID HI0000203, Hawaii”, https://aquacensus.com/water-systems/hawaii/kailua-hi0000203 (data as of October 1, 2026).