How hard is the water in Lake Zurich, IL?

Tap water hardness
84mg/L
4.9gpg
Moderately hard

Reported by Lake Zurich · May 2025

IL typical
139 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

The water in Lake Zurich carries roughly 84 mg/L of dissolved calcium and magnesium, or 4.9 grains per gallon. That is moderately hard water. The number comes from Lake Zurich, dated May 2025.

Lake Zurich on the hardness scale, with nearby cities
060120180240300360+IL typical 139Arlington Heights: 115 mg/LArlington Heights 115Hawthorn Woods: 134 mg/LHawthorn Woods 134Wauconda: 146 mg/LWauconda 146Buffalo Grove: 154 mg/LBuffalo Grove 154Mundelein: 250 mg/LMundelein 250Vernon Hills: 250 mg/LVernon Hills 250Palatine: 350 mg/LPalatine 350Lake Barrington: 573 mg/LLake Barrington 573Cary: 378 mg/LCary 378Lincolnshire: 380 mg/LLincolnshire 380Lake Zurich 84mg/L as calcium carbonate060120180240300360+IL 139Hawthorn Woods: 134 mg/LHawthorn W. 134Wauconda: 146 mg/LWauconda 146Buffalo Grove: 154 mg/LBuffalo Gr. 154Mundelein: 250 mg/LMundelein 250Palatine: 350 mg/LPalatine 350Lake Barrington: 573 mg/LLake Barri. 57384 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Lake Zurich sits 55 mg/L below the typical Illinois figure of 139. None of the 10 nearest cities we track has softer water. The range nearby runs from 115 mg/L in Arlington Heights to 573 in Lake Barrington.

What 84 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Lake Zurich

3 people × 75 gallons a day × 4.9 gpg = 1,107 grains a day. A 24,000-grain unit regenerates about every 21 days.

Size it for your household

EPA record for Lake Zurich's water system

Lake Zurich · PWSID IL0970850

No health-based violations since 2016

Serves about 19,759 people from groundwater.

Health-based
0
Monitoring or reporting
2
Open now
0

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is Lake Zurich water hard?

Somewhat. It measures about 84 mg/L (4.9 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Lake Zurich in grains per gallon?

About 4.9 gpg. One grain per gallon equals 17.1 mg/L, so 84 mg/L divided by 17.1 gives 4.9.

What size water softener do I need in Lake Zurich?

For 3 people using 75 gallons each per day, 4.9 gpg works out to about 1,107 grains a day. A 24,000-grain softener covers that with a regeneration about every 21 days.

Has the Lake Zurich water system had EPA violations?

EPA records show no health-based violations for Lake Zurich since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 192 cities in Illinois

Hardness data: TapWaterData US Water Hardness (utility report, May 6, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.