Public water system · HI0000212

Active

Wailuku

At a glance

Wailuku (PWSID HI0000212) is an active community water system in Maui County, Hawaii. It reports serving 74,511 people through 20,287 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2010.

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

Population served

74,511

Service connections

20,287

Primary source

Surface water

System type

CWS

Community water system

System record

PWSIDHI0000212

System typeCommunity water system

Activity statusActive

Population served74,511

Service connections20,287

Primary water sourceSurface water

Owner typeLocal government

Primacy agencyHI state drinking water program

City servedWailuku

StateHawaii

ZIP—

CountyMaui County

How does Wailuku compare with other water systems in Maui County?

By EPA's size categories, Wailuku is a large system (10,001 to 100,000 people). Maui County has 39 active public water systems, and Wailuku is the largest of them by population served. Its population served is about 17 times the county average of 4,338 people per system, and accounts for 44% 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 Wailuku is about 11 times 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. 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 Wailuku?

EPA lists Wailuku as owned by a local 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. 12 of the 39 active systems in Maui County (31%) are also owned by a local government.

Does Wailuku have drinking water violations?

Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2010. The violations listed here began between January 2008 and January 2010. By type: 12 monitoring and reporting. The contaminants or rules involved are Nitrate, Di(2-ethylhexyl) adipate, Di(2-ethylhexyl) phthalate and Cyanide. 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
2010-01-01	Monitoring and reportingMonitoring, Regular · code 03	Nitratecode 1040	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Di(2-ethylhexyl) adipatecode 2035	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Di(2-ethylhexyl) phthalatecode 2039	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Cyanidecode 1024	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Dalaponcode 2031	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	2,4,5-TP (Silvex)code 2110	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Diquatcode 2032	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Pentachlorophenolcode 2326	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Benzo(a)pyrenecode 2306	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Picloramcode 2040	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	Endothallcode 2033	No	Resolved
2008-01-01	Monitoring and reportingMonitoring, Regular · code 03	2,3,7,8-TCDD (dioxin)code 2063	No	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.

Wailuku: frequently asked questions

Who runs Wailuku?

Wailuku (PWSID HI0000212) is a community water system owned by a local government. It is regulated by the HI state drinking water program.

How many people does Wailuku serve?

Wailuku reports serving 74,511 people through 20,287 service connections in Maui County, Hawaii.

Where does Wailuku 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 Wailuku have any drinking water violations?

Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2010. 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 Wailuku'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, none is health-based, and the most recent began in January 2010. For current results, consult the system's annual water quality report, EPA ECHO, or the HI state drinking water program.

Where can I find Wailuku's water quality report?

As a community water system, Wailuku 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

Water system	County	Population served	Type	Source
Makawao	Maui	29,868	Community	Surface water
Lahaina	Maui	20,065	Community	Surface water
Kaanapali	Maui	8,000	Community	Groundwater
Upper Kula	Maui	7,686	Community	Surface water
Kapalua	Maui	4,200	Community	Groundwater
Kaunakakai	Maui	3,702	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, “Wailuku, PWSID HI0000212, Hawaii”, https://aquacensus.com/water-systems/hawaii/wailuku-hi0000212 (data as of October 1, 2026).