State Hub
Hawaii Water Quality
75
Utilities in database
1.5M
Residents served
18%
On private wells
2
Key contaminants tracked
Drinking Water in Hawaii
Hawaii has 75 community water systems serving approximately 1.5 million residents. Primary water sources include groundwater. The most commonly reported contaminants include disinfection byproducts, lead. 18% of Hawaii residents rely on private wells. DOH holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in Hawaii
1–25 of 75Hnl-windward-pearl Harbor
HI0000331 · 631,389 served
Waipahu-ewa-waianae
HI0000335 · 217,479 served
Wailuku
HI0000212 · 74,511 served
Joint Base Pearl Harbor-hickam
HI0000360 · 65,230 served
Mililani
HI0000367 · 50,573 served
Hilo
HI0000101 · 39,477 served
Schofield Barracks
HI0000345 · 37,920 served
Lihue-kapaa
HI0000400 · 34,854 served
Makawao
HI0000213 · 29,868 served
North Kona
HI0000131 · 29,581 served
Wahiawa
HI0000333 · 23,348 served
Lahaina
HI0000214 · 20,065 served
Marine Corps Base Hawaii
HI0000356 · 16,300 served
Kalaheo-koloa
HI0000434 · 12,660 served
Waikoloa
HI0000135 · 12,100 served
Waipio Heights
HI0000334 · 11,516 served
Waialua-haleiwa
HI0000332 · 9,996 served
South Kohala
HI0000130 · 9,612 served
Kaanapali
HI0000205 · 8,000 served
Upper Kula
HI0000215 · 7,686 served
Fort Shafter
HI0000341 · 7,067 served
Princeville
HI0000428 · 6,911 served
South Kona
HI0000132 · 6,512 served
Nctams Eastpac
HI0000357 · 6,470 served
Olaa-mountain View
HI0000112 · 6,467 served
Key Contaminant Concerns in Hawaii
Lead
Lead is a naturally occurring heavy metal that was widely used in plumbing infrastructure until it was banned for new installations in 1986. An estimated 9.2 million lead service lines still connect homes to public water mains across the United States, along with millions of homes with lead solder in their internal plumbing.
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
Hawaii Water FAQs
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Data source: Utility data from EPA SDWIS. 75 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-22