Hawaii tap water quality

118 community water systems serving 1.5 million people.

Data: U.S. EPA · How we read the data · How we check it

systems with PFAS above a federal limit

people served by them

systems EPA tested for PFAS

systems above the lead action level

PFAS: EPA's 2023–2025 testing. Lead: results from the last five years. 21 more systems have no recent lead results in EPA's database.

Largest water systems in Hawaii

Honolulu Board of Water Supply – Windward-Pearl Harbor
631,389 people · Groundwater · Hawaii
PFHxS detected
Waipahu-Ewa-Waianae Water System
217,479 people · Groundwater · Hawaii
No PFAS above limits
Wailuku Water System
74,511 people · Surface water · Hawaii
No PFAS above limits
Joint Base Pearl Harbor-Hickam Water System
65,230 people · Groundwater · Hawaii
No PFAS above limits
Mililani Water System
50,573 people · Groundwater · Hawaii
No PFAS above limits
Hilo Water System
39,477 people · Groundwater · Hawaii
No PFAS above limits
Schofield Barracks Water System
37,920 people · Groundwater · Hawaii
No PFAS above limits
Lihue-Kapaa Water System
34,854 people · Surface water · Hawaii
No PFAS above limits
Makawao Water System
29,868 people · Surface water · Hawaii
No PFAS above limitsAlso: 1 health-based violation since 2016
North Kona Water System
29,581 people · Groundwater · Hawaii
No PFAS above limits
Wahiawa Water System
23,348 people · Groundwater · Hawaii
No PFAS above limits
Lahaina Water System
20,065 people · Surface water · Hawaii
No PFAS above limits
Marine Corps Base Hawaii Water System
16,300 people · Purchased groundwater · Hawaii
No PFAS above limits
Kalaheo-Koloa Water System
12,660 people · Groundwater · Hawaii
No PFAS above limits
Waikoloa Water System
12,100 people · Groundwater · Hawaii
No PFAS above limits

Hawaii cities and towns

Honolulu

Most health-based violations since 2016

Waiawa Correctional Facility Water System
444 people · Surface water · Hawaii
Not in EPA's PFAS sampleAlso: 5 health-based violations since 2016
Waiahole Water System
300 people · Groundwater · Hawaii
Coliform bacteria violation
Keopu Water Association
250 people · Purchased groundwater · Hawaii
Not in EPA's PFAS sampleAlso: 1 health-based violation since 2016
Villa Rose Water System
30 people · Groundwater · Hawaii
Not in EPA's PFAS sampleAlso: 1 health-based violation since 2016
Maunaloa-Kaluakoi Water System
1,000 people · Purchased groundwater · Hawaii
Total trihalomethanes (TTHM) violation
Makawao Water System
29,868 people · Surface water · Hawaii
No PFAS above limitsAlso: 1 health-based violation since 2016

All Hawaii utilities on this site

Every Hawaii system serving 50,000+ people or with PFAS above a federal limit, A to Z. Download all 118 systems as CSV.

Questions

Does Hawaii tap water have PFAS?

EPA tested 44 community water systems in Hawaii for 29 PFAS between 2023 and 2025. 1 had at least one regulated PFAS detected, and 0 had an entry-point average above a 2024 federal limit. Those 0 systems serve about 0 people. Systems have until 2029 to meet the limits.

How many Hawaii water systems have violations?

6 systems in Hawaii had at least one health-based violation since 2016 (10 violations in total). 9 violations are currently listed as unaddressed.

Which Hawaii water systems are over the lead action level?

0 systems had a lead 90th percentile above the 15 ppb action level in their most recent results from the last five years. Another 21 systems have no lead results in EPA's database from the last five years. Lead depends on each home's pipes, so a test of your own tap is the only way to know your level.

Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.