Is Hawaii Tap Water Safe to Drink?
Water quality data for 7 cities across Hawaii. Find your city below.
Water quality in Hawaii varies significantly from city to city. Across 7 cities we track, hardness ranges from 20 PPM in Waikiki to 80 PPM in Honolulu, with a statewide average of 53 PPM. Most cities in Hawaii have relatively soft water, so a softener is generally unnecessary.
7
Cities
53
Avg Hardness (PPM)
80
Hardest City (PPM)
Complete Hawaii Guide
Statewide water quality overview, costs, and treatment recommendations.
Well Water in Hawaii
Testing, treatment, and common issues for private wells.
Hardest Water Rankings
Hawaii cities ranked by water hardness level.
City Comparisons
Honolulu vs Waikiki
Side-by-side water quality comparison.
Honolulu vs Pearl City
Side-by-side water quality comparison.
Pearl City vs Kapolei
Side-by-side water quality comparison.
Hawaii Cities by Water Hardness
| City | Hardness (PPM) | Level | PFAS (ppt) | Source |
|---|---|---|---|---|
| Honolulu | 80 | Moderately Hard | 3 | Groundwater (basalt aquifer) |
| Pearl City | 75 | Moderately Hard | 0 | Pearl Harbor aquifer wells |
| Kapolei | 70 | Moderately Hard | 3 | Ewa wells |
| Kailua | 65 | Moderately Hard | 0 | Windward Oahu wells |
| Hilo | 30 | Slightly Hard | 0 | Wailuku River & wells |
| Kailua-Kona | 30 | Slightly Hard | 0 | Groundwater (volcanic) |
| Waikiki | 20 | Slightly Hard | 3 | Pearl Harbor Aquifer |
Frequently Asked Questions About Hawaii Water
Is Hawaii tap water safe to drink?
Hawaii tap water meets EPA legal standards in most cities. Water hardness is relatively low across the state. Check your specific city above for detailed data.
Do I need a water softener in Hawaii?
Most Hawaii homes do not need a water softener. The state average of 53 PPM is relatively soft.
Which Hawaii city has the hardest water?
Honolulu has the hardest water in Hawaii at 80 PPM (4.7 GPG). Pearl City is second at 75 PPM. See the full ranking.
What contaminants are in Hawaii water?
The most common concerns across Hawaii are chlorine and disinfection byproducts. Each city has different levels - check your city above for specific contaminant data.
How much does a water softener cost in Hawaii?
A whole-house water softener for a typical Hawaii home costs $800-$2,500 installed, depending on capacity and brand. At 53 PPM average hardness, most homes need a 32,000-48,000 grain system. Full cost breakdown.