Honolulu
Honolulu, HI water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
hnl-windward-pearl harbor
groundwater (wells) · local government · PWSID HI0000331
Below EPA's 15 ppb lead action level at last testing.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Honolulu is a large city and the largest in Hawaii, home to roughly 371,657 residents. Honolulu's drinking water comes largely from the same regional sources that serve Hawaii: volcanic aquifers and rainfall catchment.
As elsewhere in Hawaii, the central challenge is groundwater depletion. Island aquifers are the primary supply and are sensitive to both over-pumping and contamination, as the Red Hill fuel crisis underscored.
Hawaii reuses an estimated 12% of its treated wastewater and maintains developing reuse programs; Honolulu tracks no meaningful drought conditions on the U.S. Drought Monitor scale.
Explore the Hawaii profile for statewide context, or dig into the water issues shaping Honolulu below.
Honolulu County water quality
Source: EPA SDWIS · 2026 Q1
At a glance
- Population ~371,657 (largest in Hawaii)
- Primary sources: volcanic aquifers and rainfall catchment
- Drought: no meaningful conditions
- State reuse rate: ~12% of wastewater
Common questions
Is tap water safe in Honolulu?
Honolulu's largest water system, HNL-WINDWARD-PEARL HARBOR, serves about 631,389 people. EPA records show 0 health-based violation(s) since 2016 and a most-recent 90th-percentile lead level of 0 ppb (EPA action level is 15 ppb). Always check your own provider's annual Consumer Confidence Report.
Where does Honolulu get its water?
HNL-WINDWARD-PEARL HARBOR draws primarily from groundwater (wells), part of Hawaii's supply from volcanic aquifers, rainfall catchment.
Related water issues
Groundwater Depletion
Aquifers from the Central Valley to the Ogallala are being pumped faster than they recharge, causing land subsidence and threatening long-term supply.
ExploreSaltwater Intrusion
As coastal aquifers are over-pumped and seas rise, saltwater pushes inland and contaminates freshwater supplies for cities from Florida to California.
ExplorePotable Reuse
Advanced purification turns treated wastewater into water that meets or exceeds drinking-water standards — increasingly essential in water-stressed regions.
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