Waianae Water Hardness & Quality Report (2026)
Water Hardness
0.9 grains per gallon
Source
groundwater
pH Level
7.1
neutral = 7.0
Lead
0.001 mg/L
✓ Below action level
TDS
33.8 mg/L
Est. Daily Cost
$0.04
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
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 Waianae, your appliances are currently losing 2% efficiency due to mineral buildup.
| Appliance | In Waianae | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 9.1 yrs | 8.5 yrs | — |
| Washing Machine | 13 yrs | 12 yrs | — |
| Water Heater | 15 yrs | 15 yrs | — |
Regional Water Comparison
How Waianae compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Waianae, Hawaii | 15 mg/L | 0.6 ppt | 🟢 Soft | groundwater |
| Nanakuli, Hawaii | 76 mg/L | 1.5 ppt | 🟡 Moderately Hard | groundwater |
| Makakilo, Hawaii | 75.5 mg/L | 1.5 ppt | 🟡 Moderately Hard | groundwater |
| Makakilo / Kapolei / Honokai Hale, Hawaii | 35.5 mg/L | 0.9 ppt | 🟢 Soft | groundwater |
| Schofield Barracks, Hawaii | 76.5 mg/L | 1.5 ppt | 🟡 Moderately Hard | groundwater |
National Benchmark
How Waianae compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Waianae | 15 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
Bring Badger-quality water to your Waianae home
Shop water softeners on Amazon.com →
What Makes Waianae's Water Unique?
Local geology and source profile
Waianae, Hawaii, in Honolulu County — a Honolulu County community adjacent to Makaha and Nanakuli on the west coast of Oahu — receives its water from the Board of Water Supply Honolulu, drawing from the Waianae Range basalt aquifer (Honolulu County) through the west Oahu distribution.
The very soft 15 mg/L hardness and very low TDS of 33.8 mg/L reflect west Oahu's supply from the insoluble Pliocene Waianae Volcanics basalt aquifer — among the softest water in the dataset, as Hawaiian basalt is insoluble silicate rock that produces near-pure groundwater from the basal freshwater lens stored in the vesicular basalt. The Waianae basalt aquifer — Pliocene Waianae Volcanics (insoluble basalt — primary dilutant, vesicular basalt basal lens), Pleistocene caprock (insoluble — secondary layer), and minor marine intrusion (chloride — trace TDS contributor in coastal zone).
At 15 mg/L, Waianae's water is extremely soft — no scale buildup whatsoever, appliances run at peak efficiency, and no softening is ever needed. Water is ideal for all uses. The PFAS level of 0.6 ppt is extremely low — the lowest in this dataset, no filtration needed.
Geology & Source: Waianae in Honolulu County draws from the Board of Water Supply Honolulu on the Waianae Range basalt aquifer (Honolulu County, west Oahu, Hawaii) — the Waianae basalt aquifer is developed in Pliocene Waianae Volcanics (insoluble basalt) with basal lens freshwater storage — Hawaii Honolulu County Waianae basalt Pliocene insoluble volcanic aquifer produces very soft water at 15 mg/L with TDS 33.8 mg/L.