Water Quality: Wailuku, HI
18 water systems • 142,982 people served
Multiple Health ViolationsWater Quality Summary
Wailuku is served by 18 public water systems with a combined service population of 142,982 people, and has 9 EPA Safe Drinking Water Act violations on record. Critically, 5 of those are health-based violations, meaning one or more contaminants were detected above EPA-established safe levels — a serious public health concern. Wailuku's violation count is 58% above the national average for Hawaii. Contaminants associated with violations include Disinfection Byproducts, Fecal Coliform, Stage 2 DBP.
Contaminants Found
Broad category of chemicals formed during disinfection, associated with increased cancer risk and adverse reproductive effects.
Common source: Reaction of disinfectants (chlorine, ozone, chloramines) with organic matter
Indicates direct fecal contamination; associated with diarrhea, cramps, nausea, and potential severe illness.
Common source: Human and animal fecal waste
EPA limit: Zero tolerance (any positive triggers violations)
Trihalomethanes and haloacetic acids that increase cancer risk and may cause adverse reproductive outcomes.
Common source: Chlorine disinfection reacting with natural organic matter in source water
EPA limit: TTHM: 0.080 mg/L; HAA5: 0.060 mg/L
Water Systems Serving Wailuku
| System Name | PWSID | Source | Population | Violations |
|---|---|---|---|---|
| WAILUKU | HI0000212 | Surface Water | 74,511 | 0 |
| MAKAWAO | HI0000213 | Surface Water | 29,868 | 1 |
| LAHAINA | HI0000214 | Surface Water | 20,065 | 4 |
| UPPER KULA | HI0000215 | Surface Water | 7,686 | 0 |
| KAUNAKAKAI | HI0000234 | Groundwater | 3,702 | 0 |
| LOWER KULA | HI0000247 | Surface Water | 3,522 | 2 |
| HANA | HI0000217 | Groundwater | 1,284 | 0 |
| UALAPUE | HI0000233 | Groundwater | 1,119 | 0 |
| KALAE | HI0000235 | Groundwater | 360 | 0 |
| KEANAE | HI0000219 | Groundwater | 270 | 0 |
| KAHAKULOA WATER CO. | HI0000249 | Groundwater | 150 | 1 |
| NAHIKU | HI0000220 | Groundwater | 107 | 0 |
| MAUNAOLU PLANTATION | HI0000254 | Groundwater | 100 | 0 |
| KULA NANI | HI0000255 | Surface Water | 80 | 0 |
| WEST KUIAHA MEADOWS | HI0000252 | Groundwater | 60 | 0 |
| HONOKOHAU | HI0000218 | Groundwater | 42 | 0 |
| VILLA ROSE | HI0000374 | Groundwater | 30 | 1 |
| MAUI HIGHLANDS | HI0000256 | Groundwater | 26 | 0 |
Concerned About Your Water?
A home water filter can remove common contaminants. NSF-certified filters are tested against EPA standards.
Consider a reverse osmosis system for comprehensive filtration or a carbon filter for basic improvement.
Other Cities in Hawaii
Data Sources
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). Data includes all recorded violations for active community water systems.