Mililani Town Water Hardness & Quality Report (2026)
Water Hardness
3.9 grains per gallon
Source
groundwater
pH Level
7.6
neutral = 7.0
Lead
0.008 mg/L
✓ Below action level
TDS
214.8 mg/L
Est. Daily Cost
$0.18
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 Mililani Town, your appliances are currently losing 9% efficiency due to mineral buildup.
| Appliance | In Mililani Town | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.4 yrs | 8.5 yrs | -13% |
| Washing Machine | 11.1 yrs | 12 yrs | -8% |
| Water Heater | 12.9 yrs | 15 yrs | -14% |
Regional Water Comparison
How Mililani Town compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Mililani Town, Hawaii | 67.5 mg/L | 1.3 ppt | 🟡 Moderately Hard | groundwater |
| Mililani Mauka / Launani Valley, Hawaii | 35 mg/L | 0.9 ppt | 🟢 Soft | groundwater |
| Wahiawa, Hawaii | 77.5 mg/L | 1.5 ppt | 🟡 Moderately Hard | groundwater |
| Royal Kunia, Hawaii | 76.5 mg/L | 1.5 ppt | 🟡 Moderately Hard | groundwater |
| Waipahu, Hawaii | 28 mg/L | 0.8 ppt | 🟢 Soft | groundwater |
National Benchmark
How Mililani Town compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Mililani Town | 67.5 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
Bring Badger-quality water to your Mililani Town home
Shop water softeners on Amazon.com →
What Makes Mililani Town's Water Unique?
Local geology and source profile
Mililani Town, Hawaii, in Honolulu County — a major central Oahu planned community (Mililani Town is a significant Honolulu County community — a central Oahu planned community developed by Castle and Cooke (Dole Food) beginning in the 1960s; Mililani Town is one of the most carefully planned master-planned communities in Hawaii — with a deliberate residential scale, multiple neighborhood parks and recreation centers, and a community design philosophy that has made it one of the most desirable non-resort residential communities on Oahu; Mililani Town is known for its excellent public school system (the Mililani area schools including Mililani High School are consistently among the top-performing public schools on Oahu)), a diverse Honolulu County community with a primarily Japanese-American, Filipino-American, Chinese-American, and military family population (Mililani's demographics reflect the broader Hawaii multicultural mix), adjacent to Wahiawa and Pearl City in the central Oahu corridor, home of the Mililani Town shopping complex, and a model planned suburban community — draws its municipal water supply via the Honolulu Board of Water Supply. Water hardness in Mililani Town measures 67.5 mg/L — classified as moderately soft.
Mililani Town's moderate softness reflects the central Oahu Pearl Harbor aquifer sector's calcareous-poor Hawaiian basalt character. The Pearl Harbor Aquifer at Mililani–Honolulu County draws from Quaternary Hawaiian basalt (calcareous-poor). HBWS produces the moderately soft 67.5 mg/L.
With hardness at 67.5 mg/L, Mililani Town residents enjoy moderately soft water. Honolulu Board of Water Supply consistently delivers water meeting all Hawaii DOH and EPA Safe Drinking Water Act requirements.
Geology & Source: Groundwater from the Pearl Harbor Aquifer (Oahu southern aquifer sector) via the Honolulu Board of Water Supply — the Honolulu County central Oahu Mililani Town corridor (Quaternary calcareous-poor Hawaiian basalt — the calcareous-poor central Oahu Hawaiian basalt volcanic aquifer; effective treatment); moderately soft supply at 67.5 mg/L in Honolulu County.