Hilo
Hilo, HI water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
hilo
groundwater (wells) · local government · PWSID HI0000101
Below EPA's 15 ppb lead action level at last testing.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Hilo, HI is a small but growing city, with a population near 43,263 and the 4th-largest community in Hawaii. Like much of Hawaii, Hilo draws its water primarily from volcanic aquifers and rainfall catchment.
Hilo's water outlook is shaped most by groundwater depletion — the issue that dominates planning across Hawaii. Island aquifers are the primary supply and are sensitive to both over-pumping and contamination, as the Red Hill fuel crisis underscored.
Hilo sits in a state that reuses roughly 12% of treated wastewater (developing programs) and currently experiences no meaningful drought.
For the bigger picture, see the Hawaii state water profile and the related issues below.
Hawaii County water quality
Source: EPA SDWIS · 2026 Q1
At a glance
- Population ~43,263 (4th-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 Hilo?
Hilo's largest water system, HILO, serves about 39,477 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 Hilo get its water?
HILO 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.
Explore