Prospect Heights Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
river
pH Level
8.5
neutral = 7.0
Lead
0.008 mg/L
✓ Below action level
TDS
696.5 mg/L
Est. Daily Cost
$0.40
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 Prospect Heights, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Prospect Heights | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.8 yrs | 8.5 yrs | -20% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Prospect Heights compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Prospect Heights, Illinois | ≈ 120–179 mg/L | 9.3 ppt | 🟠 Hard | river |
| Mount Prospect, Illinois | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | river |
| Arlington Heights, Illinois | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | river |
| Wheeling, Illinois | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | river |
| Buffalo Grove, Illinois | 140 mg/L | 0 ppt | 🟠 Hard | river |
National Benchmark
How Prospect Heights compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Prospect Heights | ≈ 120–179 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Prospect Heights's Water Unique?
Local geology and source profile
Prospect Heights, Illinois is served by the City of Prospect Heights Public Works Department, which provides potable water to approximately 2,275 residents in Cook County. The utility sources surface water purchased from regional suppliers, supplemented by local groundwater resources, with the administrative office at 8 North Elmhurst Road, Prospect Heights, IL 60070 (contact: 847-398-6070). The most recent Annual Drinking Water Quality Report (2023) is available through the official city website.
The water supply originates from the Lake Michigan watershed and underlying Ordovician–Silurian carbonate aquifer systems typical of northern Illinois. The region's geology is dominated by dolomite and limestone formations that contribute significant dissolved minerals to both surface and groundwater sources. This carbonate-rich bedrock, combined with glacial deposits characteristic of the area, results in a hard water supply reflecting both lacustrine and bedrock mineral sources.
Hard water causes scale accumulation in water heaters, boilers, and high-temperature appliances over time; dishwashers and washing machines require higher detergent doses, and mineral deposits form on fixtures. Periodic descaling or installation of a water softening system is recommended to extend appliance lifespan and improve cleaning performance. The utility treats all public surface water with clarification and chlorination; Prospect Heights has reported three contaminants above EPA health-based MCLGs — residents with lead concerns may contact the Cook County Department of Public Health at 708-836-8600 or the EPA's Safe Drinking Water Hotline at 800-426-4791.
Geology & Source: Lake Michigan watershed, northern Illinois; Ordovician and Silurian dolomite and limestone with glacial deposits — carbonate bedrock readily dissolves calcium and magnesium, producing hard supply
Other Illinois Water Reports
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Frequently Asked Questions
Is Prospect Heights's water safe to drink?
Do I need a water softener in Prospect Heights?
How does Prospect Heights compare to the USA average?
Data Sources & Methodology
Water quality data for Prospect Heights 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.