Aliamanu / Salt Lakes / Foster Village Water Hardness & Quality Report (2026)
Water Hardness
~0–59 mg/L
Softestimated · not lab-verified
Source
groundwater
pH Level
7.3
neutral = 7.0
Lead
0.004 mg/L
✓ Below action level
TDS
91.4 mg/L
Est. Daily Cost
$0.08
energy & soap waste
Source: See methodology section below · 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 Aliamanu / Salt Lakes / Foster Village, your appliances are currently losing 4% efficiency due to mineral buildup.
| Appliance | In Aliamanu / Salt Lakes / Foster Village | 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 Aliamanu / Salt Lakes / Foster Village compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Aliamanu / Salt Lakes / Foster Village, Hawaii | ≈ 0–59 mg/L | 0.9 ppt | 🟢 Soft | groundwater |
| Halawa Heights, Hawaii | ≈ 0–60 mg/L | 1 ppt | 🟢 Soft | groundwater |
| Halawa, Hawaii | ≈ 0–60 mg/L | 1 ppt | 🟢 Soft | groundwater |
| Airport, Hawaii | ≈ 0–60 mg/L | 1.3 ppt | 🟢 Soft | groundwater |
| Joint Base Pearl Harbor Hickam, Hawaii | 20 mg/L | 0.7 ppt | 🟢 Soft | groundwater |
National Benchmark
How Aliamanu / Salt Lakes / Foster Village compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Aliamanu / Salt Lakes / Foster Village | ≈ 0–59 mg/L | 🟢 None |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Aliamanu / Salt Lakes / Foster Village's Water Unique?
Local geology and source profile
The Aliamanu water utility (system ID HI0000337), operated under the Board of Water Supply (BWS), serves approximately 6,406 residents in the Aliamanu / Salt Lakes / Foster Village area of Honolulu County, Hawaii, including the Salt Lake community and Aliamanu Military Reservation via the Joint Base Pearl Harbor Hickam Water System. Water is sourced exclusively from purchased groundwater drawn from Oahu's basaltic aquifers, with no surface water reservoirs or rivers used. Treatment involves standard disinfection and compliance monitoring to meet Hawaii Department of Health (DOH) and EPA standards.
The recharge zones of Oahu's eastern Ko'olau Range feed precipitation into the fractured Ko'olau basalt formation, a thick sequence of Tertiary volcanic rocks. This geology yields very soft water due to the absence of carbonate-rich sediments; rainwater picks up few dissolved minerals as it travels through the inert basaltic matrix. The aquifer provides natural filtration, contributing to the supply's pristine character with low mineral content and total dissolved solids of just 91.4 mg/L.
Very soft water poses no risk of scale buildup, protecting water heaters, dishwashers, and washing machines from limescale damage while minimizing maintenance needs. Soap lathers easily, reducing detergent use, though very soft water may feel slick on skin. No water softener is recommended or needed. Water quality is excellent, earning an A grade (87/100) with no contaminants exceeding EPA limits among 38 tested substances; pH measures 7.3, lead is well below action levels at 0.004 mg/L, and PFAS is minimal at 0.9 ppt.
Geology & Source: Oahu Ko'olau basalt formation — Cenozoic Pleistocene basaltic lava flows; no carbonate minerals; rapid recharge through fractured volcanic rock produces minimal calcium and magnesium — very soft water
Other Hawaii Water Reports
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Frequently Asked Questions
Is Aliamanu / Salt Lakes / Foster Village's water safe to drink?
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How does Aliamanu / Salt Lakes / Foster Village compare to the USA average?
Data Sources & Methodology
Water quality data for Aliamanu / Salt Lakes / Foster Village is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.
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.
pH
Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.
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.
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.
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.
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.