Is Kailua-Kona, HI Tap Water Safe to Drink?
Yes, Kailua-Kona tap water is safe to drink. Hardness is low at 30 PPM, and no contaminants exceed health guidelines. Most homes here don't need treatment.
Hardness Scale: Where Kailua-Kona Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Kailua-Kona Compares
Kailua-Kona's water is 78% softer than the national average of 138 PPM - ranking in the bottom 84% for hardness nationwide. Most homes here do not need a softener. Within Hawaii, it ranks #6 of 7 cities (43% below the state average of 53 PPM). Among smaller cities, Kailua-Kona ranks #218 of 288 for hardness.
What Kailua-Kona's Water Means for Your Home
Hardness: 30 PPM - Low Concern
Kailua-Kona's water is slightly hard at 30 PPM. Most households won't notice any issues at this level. Scale buildup is minimal, and a water softener would be overkill. Kailua-Kona is softer than 84% of US cities. If you're thinking about water treatment, contaminant filtration is where to focus your money, not softening.
Contaminants & Safety
Beyond hardness, Kailua-Kona's water is within EPA guidelines for regulated contaminants. Chlorine is relatively low at 0.8 mg/L. 5 contaminants exceed EWG's stricter health guidelines, though all are within legal limits.. Want the full picture? Request your utility's annual Consumer Confidence Report for neighborhood-level data.
| Contaminant | Detected | Health Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Hardness (as CaCO₃) | 30 PPM | < 60 PPM | No federal limit | ✓ OK |
| Total Dissolved Solids | 50 PPM | < 300 PPM | 500 PPM | ✓ OK |
| PFAS (total) | Not tested | — | No total limit | N/A |
| Lead | 2.4 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ✓ Low |
| Chlorine / Chloramine | 0.8 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | 1.48 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Good news for Kailua-Kona residents. Your water quality is generally good. Most homes in this area do not need a water softener. If you have concerns about lead (especially in buildings constructed before 1986) or chlorine taste, a point-of-use filter is the most practical and cost-effective solution.
How to Test Your Water in Kailua-Kona
City-wide data is a solid starting point, but your specific tap might differ based on plumbing age, distance from the treatment plant, or seasonal changes.
Free option: Request Hawaii Dept of Water Supply's annual Consumer Confidence Report for official city-level data.
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About Kailua-Kona's Water Supply
Water Utility: Hawaii Dept of Water Supply
Water Source: Groundwater (volcanic) (Groundwater)
Population Served: 1,945
Hardness: 30 PPM (1.8 grains per gallon)
Kailua-Kona draws its drinking water from groundwater sources — Groundwater (volcanic). Groundwater typically requires less treatment than surface water because the earth acts as a natural filter. The tradeoff: dissolved minerals from underground rock formations, which is why mineral content varies by aquifer depth and geology. The geological profile determines hardness, iron, and trace mineral levels. The system serves 2,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request Hawaii Dept of Water Supply's Consumer Confidence Report (CCR) or test your own tap.
ZIP Codes Covered by This Report
This water quality data applies to all areas served by Hawaii Dept of Water Supply in Kailua-Kona, HI, including ZIP codes:
96556, 96558, 96598, 96704, 96708, 96713, 96719, 96725, 96726, 96737, 96738, 96739, 96740, 96743, 96750, 96753, 96755, 96768, 96772, 96779, 96788, 96790
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Compare Kailua-Kona to Other Hawaii Cities
Frequently Asked Questions About Kailua-Kona Water
Is Kailua-Kona tap water safe to drink?
Where does Kailua-Kona's water come from?
Do I need a water softener in Kailua-Kona?
Can I drink Kailua-Kona tap water straight from the faucet?
How does Kailua-Kona compare to the Hawaii average?
What water filter is best for Kailua-Kona?
Data sources: Lead and copper data from EPA Safe Drinking Water Act LCR reporting. Contaminant data from utility-reported testing results. PFAS data from EPA UCMR5 (2023–2025). Hardness from USGS and municipal reports. Data reflects system-level testing results and may not match your specific tap due to neighborhood plumbing, season, or recent utility changes. For your utility's latest results, request their Consumer Confidence Report (CCR). Our methodology. Last updated: 2026-02-24.