D39/100
Wailuku Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 141,757 residents · Hawaii
What's In Wailuku's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2010.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
WAILUKU
Population Served
74,511
Water Source
Surface Water
System ID
HI0000212
MAKAWAO
Population Served
29,868
Water Source
Surface Water
System ID
HI0000213
LAHAINA
Population Served
20,065
Water Source
Surface Water
System ID
HI0000214
UPPER KULA
Population Served
7,686
Water Source
Surface Water
System ID
HI0000215
HANA
Population Served
1,284
Water Source
Groundwater
System ID
HI0000217
UALAPUE
Population Served
1,119
Water Source
Groundwater
System ID
HI0000233
KAUNAKAKAI
Population Served
3,702
Water Source
Groundwater
System ID
HI0000234
LOWER KULA
Population Served
3,522
Water Source
Surface Water
System ID
HI0000247
Frequently Asked Questions About Wailuku Water
Is Wailuku tap water safe to drink?
Wailuku, Hawaii tap water receives a grade of D (39/100), which is considered poor. 1 contaminant(s) exceed EPA maximum contaminant levels and 349 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Wailuku's water?
Of the 70 contaminants tested in Wailuku's water supply, the most notable include Copper (90th percentile), Lead (90th percentile), chlorate. 1 contaminant(s) exceed EPA legal limits (MCLs). 3 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Wailuku have any water quality violations?
Yes, Wailuku has 349 EPA violation(s) on record, with the most recent in 2020. Violation types include TT, MR, MCL. 233 of these are health-based violations, which are the most serious category.
Do I need a water filter in Wailuku?
Based on EPA data, using a water filter in Wailuku is recommended. 1 contaminant(s) exceed legal limits. An NSF-certified filter — such as a reverse osmosis or activated carbon system — can effectively reduce many common contaminants. Choose a filter certified to remove the specific contaminants found in your area.
Where does Wailuku's tap water come from?
Wailuku's drinking water is sourced from surface water and supplied by WAILUKU and 7 other water system(s). The system serves approximately 141,757 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Wailuku's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Wailuku's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Wailuku's water compare to other cities in Hawaii?
Wailuku's water quality score of 39/100 earns a grade of D, which is considered poor. This is a concerning score that suggests significant water quality issues. Visit our Hawaii state page to see how all cities in the state compare.
What should I do if I'm concerned about Wailuku's water quality?
If you have concerns about Wailuku's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (WAILUKU) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.