Public water system · HI0000306
ActiveWaimano Ridge
At a glance
Waimano Ridge (PWSID HI0000306) is an active non-transient non-community water system in Honolulu County, Hawaii. It reports serving 545 people through 52 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2015.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
545
Service connections
52
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Waimano Ridge compare with other water systems in Honolulu County?
By EPA's size categories, Waimano Ridge is a small system (501 to 3,300 people). 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 Waimano Ridge is about 27% above 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. 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 Waimano Ridge?
EPA lists Waimano Ridge 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. 16 of the 38 active systems in Honolulu County (42%) are also privately owned.
Does Waimano Ridge have drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2015. The violations listed here began between April 1999 and October 2015. By type: 8 monitoring and reporting and 1 contaminant level above the legal limit. The contaminants or rules involved are Chlorine, Diquat, Cyanide and Di(2-ethylhexyl) phthalate. EPA lists 8 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 |
|---|---|---|---|---|
| 2015-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Diquatcode 2032 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Cyanidecode 1024 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Di(2-ethylhexyl) phthalatecode 2039 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Di(2-ethylhexyl) adipatecode 2035 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Benzo(a)pyrenecode 2306 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Endothallcode 2033 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 2,3,7,8-TCDD (dioxin)code 2063 | No | Resolved |
| 1999-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
All 9 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.
Waimano Ridge: frequently asked questions
Who runs Waimano Ridge?
Waimano Ridge (PWSID HI0000306) is a non-transient non-community water system privately owned. It is regulated by the HI state drinking water program.
How many people does Waimano Ridge serve?
Waimano Ridge reports serving 545 people through 52 service connections in Honolulu County, Hawaii.
Where does Waimano Ridge 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 Waimano Ridge have any drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2015. 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 Waimano Ridge'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 9 violations for this system; 1 is health-based, and the most recent began in October 2015. For current results, consult EPA ECHO, or the HI state drinking water program.
Where can I find Waimano Ridge's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Waimano Ridge 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, “Waimano Ridge, PWSID HI0000306, Hawaii”, https://aquacensus.com/water-systems/hawaii/waimano-ridge-hi0000306 (data as of October 1, 2026).