Public water system · HI0000135
ActiveWaikoloa
At a glance
Waikoloa (PWSID HI0000135) is an active community water system in Hawaii County, Hawaii. It reports serving 12,100 people through 2,120 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in March 2010.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
12,100
Service connections
2,120
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Waikoloa compare with other water systems in Hawaii County?
By EPA's size categories, Waikoloa is a large system (10,001 to 100,000 people). Hawaii County has 39 active public water systems, and Waikoloa is the 3rd-largest of them by population served. Its population served is about 3.3 times the county average of 3,693 people per system, and accounts for 8.4% of the 144,021 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 Waikoloa is about 81% above 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 Waikoloa?
EPA lists Waikoloa 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. 13 of the 39 active systems in Hawaii County (33%) are also privately owned.
Does Waikoloa have drinking water violations?
EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in March 2010. The violations listed here began between July 1992 and March 2010. By type: 3 monitoring and reporting and 3 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 of them). EPA lists 4 as resolved and 2 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 |
|---|---|---|---|---|
| 2010-03-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2010-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2000-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2000-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1993-07-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1992-07-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
All 6 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.
Waikoloa: frequently asked questions
Who runs Waikoloa?
Waikoloa (PWSID HI0000135) is a community water system privately owned. It is regulated by the HI state drinking water program.
How many people does Waikoloa serve?
Waikoloa reports serving 12,100 people through 2,120 service connections in Hawaii County, Hawaii.
Where does Waikoloa 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 Waikoloa have any drinking water violations?
EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in March 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 Waikoloa'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 6 violations for this system; 3 are health-based, and the most recent began in March 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 Waikoloa's water quality report?
As a community water system, Waikoloa 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 Hawaii County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Hilo | Hawaii | 39,477 | Community | Groundwater |
| North Kona | Hawaii | 29,581 | Community | Groundwater |
| South Kohala | Hawaii | 9,612 | Community | Surface water |
| South Kona | Hawaii | 6,512 | Community | Groundwater |
| Olaa-Mountain View | Hawaii | 6,467 | Community | Groundwater |
| North Kohala | Hawaii | 4,933 | 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, “Waikoloa, PWSID HI0000135, Hawaii”, https://aquacensus.com/water-systems/hawaii/waikoloa-hi0000135 (data as of October 1, 2026).