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Water Hardness in 96740

Kailua Kona, Hawaii · Hawaii County

20 PPM
1.2 GPG
Soft
0Soft60120180300+
Verified — Annual Water Quality Report

Dataset updated March 9, 2026Matched to 6 water systemsTap readings can vary by utility zone, treatment, and plumbing. Methodology

Source context

How this ZIP reading is built

This ZIP reading is built from 6 matched water systems. When more than one system is matched, the displayed value is weighted toward larger known service populations when that data is available.

Source basis
5 verified treated-water sources
6 matched systems total for this ZIP; treated-water reports are prioritized when available.
Water source profile
Primarily groundwater
Groundwater commonly picks up calcium and magnesium after contact with rock and soil. This profile is weighted by known population served across matched systems.
Data recency
March 9, 2026
Dataset rebuilt March 9, 2026; individual utility reporting years can vary.

Hardness is a mineral-content reading, not a drinking-water safety rating. Use it for scale, appliance, and softener decisions; check your utility report or test your tap before sizing treatment equipment. See how we calculate local readings.

Water Systems Serving 96740

These are the systems matched to this ZIP code. The displayed ZIP value is weighted toward larger known service populations when population data is available.

6 water systems
PWSID is the public water system identifier. Data Source shows whether the hardness value comes from a treated-water report, USGS monitoring, or a local estimate; source year is shown when available.
Hilo
HI0000101
Soft
15 PPMgroundwater39,477 servedVerified — Annual Water Quality Report
Source water: 1023 PPM
North Kona
HI0000131
Soft
15 PPMgroundwater29,581 servedVerified — Annual Water Quality Report
Source water: 1023 PPM
Waikoloa
HI0000135
Soft
15 PPMgroundwater12,100 servedVerified — Annual Water Quality Report
Source water: 1023 PPM
Hawaii Volcanoes Nat.Park
HI0000146
Soft
15 PPMgroundwater4,201 servedVerified — Annual Water Quality Report
Source water: 1023 PPM
Kaupulehu
HI0000163
Soft
15 PPMgroundwater1,945 servedVerified — Annual Water Quality Report
Source water: 1023 PPM
Showing the first 5 systems. Expand to review all matched systems.

Nearby Zip Codes

967381509672515967501596743289672715

What This Means For You

Recommendations are based on the displayed ZIP hardness reading. Confirm your tap reading before sizing or buying treatment equipment.

Your Water Is Soft

Your water hardness is in the soft range. You likely don't need a water softener. Enjoy your naturally soft water!

Know your water hardness?

If you've tested your water or have your utility's CCR report, share your reading to help us improve accuracy for Kailua Kona, HI (96740).

Submit Your Data

Frequently Asked Questions

Is the water hard in Kailua Kona, HI (96740)?

The average water hardness in 96740 is 20 PPM (1.2 GPG), which is classified as soft.

Do I need a water softener in 96740?

At 20 PPM, your water is relatively soft. A water softener is generally not necessary.

Is hard water in 96740 safe to drink?

Water hardness itself is a mineral-content reading, not a drinking-water safety rating. Calcium and magnesium are naturally occurring minerals, but you should check your utility's Consumer Confidence Report for contaminant and compliance information.

How many water systems serve 96740?

Zip code 96740 in Kailua Kona, Hawaii is served by 6 water systems.

Learn More About Your Water

Water Hardness Scale: PPM and GPG Chart

Use the USGS water hardness scale to compare PPM, GPG, and mg/L levels from soft to very hard water.

10 min read

How to Test Water Hardness at Home

Compare free lookups, soap tests, test strips, liquid drop kits, and lab tests for measuring water hardness.

8 min read