Prospect Heights Water Hardness & Quality Report (2026)
Water Hardness
15.7 grains per gallon
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
$0.72
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 Prospect Heights, your appliances are currently losing 36% efficiency due to mineral buildup.
| Appliance | In Prospect Heights | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 1.5 yrs | 8.5 yrs | -82% |
| Washing Machine | 3.7 yrs | 12 yrs | -69% |
| Water Heater | 5 yrs | 15 yrs | -67% |
Regional Water Comparison
How Prospect Heights compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Prospect Heights, Illinois | 268.5 mg/L | 9.3 ppt | 🔴 Very Hard | river |
| Mount Prospect, Illinois | 177 mg/L | 6.2 ppt | 🟠 Hard | river |
| Arlington Heights, Illinois | 261 mg/L | 9.1 ppt | 🔴 Very Hard | river |
| Wheeling, Illinois | 204.5 mg/L | 7.2 ppt | 🔴 Very Hard | river |
| Buffalo Grove, Illinois | 248 mg/L | 8.6 ppt | 🔴 Very Hard | river |
National Benchmark
How Prospect Heights compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Prospect Heights | 268.5 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Prospect Heights's Water Unique?
Local geology and source profile
Prospect Heights, Illinois, in Cook County — a Cook County city adjacent to Wheeling and Mount Prospect in the northwest Chicago metro — receives its municipal water from Illinois American Water or the Northwest Waterworks, drawing from a supply that includes both Lake Michigan water and local Silurian dolomite groundwater in the north Cook County distribution zone.
The very hard 268.5 mg/L hardness and elevated TDS of 696.5 mg/L are dramatically harder than standard Chicago metropolitan Lake Michigan water (Chicago: ~120-140 mg/L), indicating Prospect Heights' north Cook County supply draws a significant proportion from local Silurian Niagara Dolomite groundwater wells (which typically measure 400-600 mg/L hardness in the north Chicago suburbs) blended with softer Lake Michigan distribution water. The resulting blend produces the very hard north Chicago metro reading.
At 268.5 mg/L, Prospect Heights' water is very hard. A water softener is strongly recommended. Scale builds rapidly on heating surfaces and appliances, and water heaters require annual descaling without softening. The PFAS level of 9.3 ppt warrants a certified reverse osmosis drinking water filter — the Cook County north Chicago industrial corridor, Glenview Naval Air Station (former AFFF site — the dominant north suburban Cook County PFAS source), and the Chicago metro PFAS complex contribute to Prospect Heights' elevated readings.
Geology & Source: Prospect Heights in Cook County draws from Illinois American Water on a blend of Lake Michigan and local wells (Cook County, north Chicago metro) — the Silurian dolomite aquifer (Silurian Niagara Dolomite — very hard) blends with Lake Michigan distribution — Illinois Cook County Lake Michigan-Silurian dolomite blend produces very hard water at 268.5 mg/L with TDS 696.5 mg/L in this Cook County Illinois city.