How does Deerfield's water compare to the national average?

The USA national average is 151 mg/L. Deerfield (≈ 120–179 mg/L) is 1 mg/L softer than average.

Deerfield Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

river

pH Level

7.8

neutral = 7.0

Lead

0.003 mg/L

✓ Below action level

TDS

257.5 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 Deerfield, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Deerfield	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 Deerfield compares to its nearest neighbours

City	Hardness	Risk	Source
▶ Deerfield, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Highland Park, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Northbrook, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Lake Forest, Illinois	≈ 120–179 mg/L	🟠 Hard	river
Wheeling, Illinois	≈ 120–179 mg/L	🟠 Hard	river

National Benchmark

How Deerfield compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Deerfield	≈ 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 Deerfield's Water Unique?

Local geology and source profile

Source: RiverTDS: 257.5 mg/LpH: 7.8

The Village of Deerfield Public Works Department operates the local water utility, serving approximately 18,000 residents in Deerfield, Illinois, in Lake and Cook Counties north of Chicago. Groundwater is sourced from local wells tapping into regional aquifers, with no reliance on surface water sources such as Lake Michigan. Water is treated at the village's water treatment facilities and distributed throughout the service area. Compliance with EPA standards is maintained as detailed in annual Drinking Water Quality Reports, including the 2023 Annual Drinking Water Quality Report.

Deerfield's supply originates within the northeastern Illinois watershed, shaped by Paleozoic limestone and dolomite bedrock — particularly Silurian and Devonian formations — that characterises the local geology. These carbonate rocks dissolve gradually, contributing elevated calcium and magnesium to the water. Glacial till overlays further shape recharge infiltration patterns, producing a distinctly hard character throughout the aquifer system, with the dominant sedimentary geology ensuring a consistently mineralised profile.

Hard water in Deerfield leads to scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. Kettles and faucets show white deposits, and soap lathering is less effective, requiring more detergent. Regular deliming of appliances and annual heater flushing are advised; a water softener is recommended for households. The 2023 Annual Drinking Water Quality Report shows no MCL violations, though independent analyses detect arsenic, hexavalent chromium, bromodichloromethane, chloroform, and trihalomethanes above health guidelines; filters are suggested for enhanced protection.

Geology & Source: Northeastern Illinois Paleozoic aquifers — Silurian and Devonian limestone and dolomite bedrock; glacial till overlays shape recharge infiltration; carbonate dissolution yields consistently hard, calcium- and magnesium-rich groundwater

Other Illinois Water Reports

Highland Park

≈ 120–179 mg/L

🟠 Hard

Northbrook

≈ 120–179 mg/L

🟠 Hard

Lake Forest

≈ 120–179 mg/L

🟠 Hard

Wheeling

≈ 120–179 mg/L

🟠 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 Deerfield's water safe to drink?

Yes. Deerfield'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 Deerfield?

At ≈ 120–179 mg/L (Hard), Deerfield'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 Deerfield compare to the USA average?

The USA national average is 151 mg/L. Deerfield (≈ 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 Deerfield 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.