Hawaii Water Systems
118 community water systems in Hawaii, ranked by violation count. Data from EPA Safe Drinking Water Information System (SDWIS).
Hawaii operates 118 community water systems regulated by the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act. Together these utilities serve an estimated 1,506,224 residents, each filing compliance results with the state's primacy agency and, for federally listed contaminants, with the U.S. Environmental Protection Agency.
Across the state, SDWIS records contain 29 total violations, of which 16 systems carry at least one active health-based violation, a Maximum Contaminant Level (MCL) exceedance or treatment-technique failure. That represents roughly 14% of Hawaii systems.
Violation counts reflect both infrastructure realities and reporting diligence, a state with more small rural systems will accumulate more monitoring-type violations without necessarily delivering worse water. Health-based violations are the stronger safety signal. A past violation does not itself indicate current unsafe water; utilities must notify customers, remediate, and publish an annual Consumer Confidence Report. All numbers below draw directly from the federal SDWIS record.
Which water systems have violations? (16)
| # | System Name | Violations | Health |
|---|---|---|---|
| 1 | MOLOAA IRRIGATION COOPERATIVE Anahola | 10 | Yes |
| 2 | WAIAWA CORRECTIONAL FACILITY Pearl City | 5 | Yes |
| 3 | HILO Hilo | 1 | Yes |
| 4 | MAKAWAO Wailuku | 1 | Yes |
| 5 | LAHAINA Wailuku | 1 | Yes |
| 6 | LOWER KULA Wailuku | 1 | Yes |
| 7 | PAHALA Hilo | 1 | Yes |
| 8 | MAUNALOA-KALUAKOI Maunaloa | 1 | Yes |
| 9 | KUKUIHAELE Hilo | 1 | Yes |
| 10 | WAIAHOLE Honolulu | 1 | Yes |
| 11 | KEOPU WATER ASSOCIATION Holualoa | 1 | Yes |
| 12 | KAHAKULOA WATER CO. Wailuku | 1 | Yes |
| 13 | SHASTA CASCADE MOBILEHOME PARK Honolulu | 1 | Yes |
| 14 | KAILUA Puunene | 1 | Yes |
| 15 | PEPEEKEO WATER ASSOCIATION Hilo | 1 | Yes |
| 16 | VILLA ROSE Wailuku | 1 | Yes |
Systems with No Violations (102)
102 water systems in Hawaii have zero recorded violations. Showing the 50 largest by population served.
All Water Systems in Hawaii (118)
Page 2 of 3, ordered by population served.
Frequently Asked Questions
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About This Data
Water system data is from the EPA Safe Drinking Water Information System (SDWIS). Health-based violations include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations that may pose a direct risk to public health. Only community water systems (CWS) are included.
Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services U.S. Environmental Protection Agency, SDWIS Federal Reporting Services
Read our methodology - how this data is sourced, computed, and verified.