How does Kalihi-Palama's water compare to the national average?

The USA national average is 151 mg/L. Kalihi-Palama (≈ 0–59 mg/L) is 121 mg/L softer than average.

Kalihi-Palama Water Hardness & Quality Report (2026)

Water Hardness

soft

~0–59 mg/L

Soft

estimated · not lab-verified

Source

groundwater

pH Level

7.5

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

149.1 mg/L

Est. Daily Cost

$0.08

energy & soap waste

Source: See methodology section below · Updated 2026

soft~0–59 mg/LSoft · est.

0–60

mg/L

Soft

61–120

mg/L

Moderately Hard

121–180

mg/L

Hard

180+

mg/L

Very Hard

Appliance Damage Report

In Kalihi-Palama, your appliances are currently losing 4% efficiency due to mineral buildup.

Appliance	In Kalihi-Palama	Soft Water City	Efficiency Loss
Kettle	8.2 yrs	8.5 yrs	-4%
Washing Machine	11.5 yrs	12 yrs	-4%
Water Heater	14.4 yrs	15 yrs	-4%

Regional Water Comparison

How Kalihi-Palama compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Kalihi-Palama, Hawaii	≈ 0–59 mg/L	1.1 ppt	🟢 Soft	groundwater
Liliha - Kapalama, Hawaii	≈ 0–60 mg/L	0.6 ppt	🟢 Soft	groundwater
Honolulu, Hawaii	≈ 60–120 mg/L	5 ppt	🟡 Moderately Hard	groundwater
Downtown, Hawaii	≈ 0–60 mg/L	0.9 ppt	🟢 Soft	groundwater
Kaka'ako, Hawaii	≈ 0–60 mg/L	1.3 ppt	🟢 Soft	groundwater

National Benchmark

How Kalihi-Palama compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Kalihi-Palama	≈ 0–59 mg/L	🟢 None
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

Bring Scarsdale-quality water to your Kalihi-Palama home

Shop water softeners on Amazon.com →

Shop Now

What Makes Kalihi-Palama's Water Unique?

Local geology and source profile

Source: GroundwaterTDS: 149.1 mg/LpH: 7.5

The Kalihi-Palama area of Honolulu, Oahu, Hawaii is served by the Board of Water Supply (BWS), which manages water resources for Honolulu County. Primary water sources include Kalihi Stream and contributions from the Honolulu aquifer system, which taps groundwater from volcanic formations. Treatment facilities process water to meet state and federal standards before distribution to the service area.

The Kalihi watershed drains volcanic terrain on the Koʻolau mountain range, composed primarily of Quaternary basaltic lava flows. The underlying geology consists of Tertiary volcanic rocks forming the Honolulu aquifer, which supplies groundwater to the region. This volcanic geology, combined with limited carbonate rock formations, results in naturally soft water with relatively low dissolved mineral content — a characteristic typical of Hawaiian water supplies across the islands.

As a soft water supply, residents experience minimal scaling in appliances, reduced soap consumption, and lower maintenance costs for water heaters and plumbing fixtures. Water softeners are generally not necessary. However, soft water may require corrosion control treatment to prevent copper and lead leaching from pipes, a concern the BWS addresses through pH adjustment and treatment protocols. The BWS implements chlorination and filtration to ensure drinking water safety; historical monitoring has noted elevated fecal and total coliform densities in Kalihi Stream during wet weather conditions, which treatment processes are designed to address.

Geology & Source: Kalihi Stream watershed, Oahu; Quaternary basaltic lava flows over Tertiary volcanic rocks forming the Honolulu aquifer — limited limestone deposits result in naturally soft water with low mineral content, typical of Hawaiian supplies

Other Hawaii Water Reports

Liliha - Kapalama

≈ 0–60 mg/L

🟢 Soft

Honolulu

≈ 60–120 mg/L

🟡 Moderately Hard

Downtown

≈ 0–60 mg/L

🟢 Soft

Kaka'ako

≈ 0–60 mg/L

🟢 Soft

Report an Issue

Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.

All reports are reviewed by our team. Thank you for supporting data quality!

Frequently Asked Questions

Is Kalihi-Palama's water safe to drink?

Yes. Kalihi-Palama's water meets all federal safety standards. The hardness is ≈ 0–59 mg/L (Soft), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Kalihi-Palama?

Kalihi-Palama's water is soft at ≈ 0–59 mg/L. A water softener is generally not necessary, though a carbon filter can improve taste and remove any remaining chlorine.

How does Kalihi-Palama compare to the USA average?

The USA national average is 151 mg/L. Kalihi-Palama (≈ 0–59 mg/L) is 121 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Kalihi-Palama is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

Water Hardness

Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

TDS — Total Dissolved Solids

Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.

Measured

PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances

EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.

Modelled

Lead

Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.

Calculated

Appliance Lifespan

Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.