Highland Park Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

river

pH Level

8.4

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

499.5 mg/L

Est. Daily Cost

$0.40

energy & soap waste

Source: See methodology section below · Updated 2026

hard~120–179 mg/LHard · est.

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 Highland Park, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Highland Park	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 Highland Park compares to its nearest neighbours

City	Hardness	Risk	Source
▶ Highland Park, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Deerfield, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Northbrook, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Lake Forest, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Winnetka, Illinois	≈ 180+ mg/L	🔴 Very Hard	river

National Benchmark

How Highland Park compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Highland Park	≈ 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 Highland Park's Water Unique?

Local geology and source profile

Source: RiverTDS: 499.5 mg/LpH: 8.4

Highland Park Municipal Water Company serves the city of Highland Park in Lake County, Illinois, providing drinking water to approximately 30,000 residents across 12 square miles in the northern Chicago suburbs. The primary source is Lake Michigan, withdrawn via the city's intake crib in Lake County waters, potentially supplemented by local groundwater wells. Water is treated at the Highland Park Water Filtration Plant, which employs conventional treatment including screening, coagulation, sedimentation, filtration, and disinfection with chloramines. Fluoride is added at 0.7 mg/L, and distribution serves residential, commercial, and institutional users across this North Shore community.

The supply originates from the Lake Michigan watershed, North America's largest freshwater system by surface area, underlain by Precambrian bedrock and overlain by glacial deposits and Paleozoic carbonates. Key formations include the Silurian Racine and Waukegan dolomites, which outcrop along the lakeshore and contribute to mineral dissolution. Where groundwater supplements the supply, it interfaces with the Galena-Platteville limestone and shallower dolomite units prone to karst dissolution, leaching hardness ions and imparting an overall hard character shaped by prolonged rock-water interaction in carbonate-rich strata.

Hard water leads to moderate scale buildup on fixtures, reducing efficiency in water heaters, dishwashers, and washing machines by 20–30% over time due to calcium deposits insulating heating elements. Faucet aerators and showerheads clog noticeably within 1–2 years. Monthly vinegar soaks for removable parts and annual appliance descaling are advised; a water softener is recommended to extend appliance life and improve soap lathering. pH is maintained at 7.5–8.5 for corrosion control; 2026 compliance notices flag trace Dibromoacetic acid and p-Cresol below MCLs. Lead and copper adherence is strong, with 90th percentile copper under 1.0 mg/L; no PFAS exceedances reported, though monitoring continues.

Geology & Source: Lake Michigan via intake crib — Silurian Racine and Waukegan dolomites, Precambrian bedrock overlain by Paleozoic carbonates; supplemental groundwater from Galena-Platteville limestone; carbonate dissolution yields hard supply

Other Illinois Water Reports

Deerfield

≈ 120–179 mg/L

🟠 Hard

Northbrook

≈ 120–179 mg/L

🟠 Hard

Lake Forest

≈ 120–179 mg/L

🟠 Hard

Winnetka

≈ 180+ mg/L

🔴 Very Hard

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Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.

All reports are reviewed by our team. Thank you for supporting data quality!

Frequently Asked Questions

Is Highland Park's water safe to drink?

Yes. Highland Park's water meets all federal safety standards. The hardness is ≈ 120–179 mg/L (Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Highland Park?

At ≈ 120–179 mg/L (Hard), Highland Park's water will cause significant limescale on kettles, washing machines, and water heaters. A water softener or descaler is strongly recommended to extend appliance lifespan and reduce energy bills by up to 20%.

How does Highland Park compare to the USA average?

The USA national average is 151 mg/L. Highland Park (≈ 120–179 mg/L) is 1 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Highland Park is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

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.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

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.

Measured

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.

Modelled

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.

Calculated

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.