Hard water in Algonquin, IL

Tap water hardness
378mg/L
22.1gpg
Very hard

Reported by Algonquin · September 2025

IL typical
139 mg/L
EPA health violations since 2016
0
Softener for 3 people
48k grain
Data
Utility report

Tap water in Algonquin has about 378 mg/L of hardness, which is 22.1 grains per gallon. On the USGS scale that counts as very hard. The number comes from Algonquin, dated September 2025.

Algonquin on the hardness scale, with nearby cities
060120180240300360+IL typical 139West Dundee: 14 mg/LWest Dundee 14Huntley: 31 mg/LHuntley 31Pingree Grove: 65 mg/LPingree Grove 65Carpentersville: 67 mg/LCarpentersville 67Elgin: 111 mg/LElgin 111Lake in the Hills: 283 mg/LLake in the Hills 283Gilberts: 328 mg/LGilberts 328Crystal Lake: 388 mg/LCrystal Lake 388Cary: 378 mg/LCary 378Lake Barrington: 573 mg/LLake Barrington 573Algonquin 378off the scalemg/L as calcium carbonate060120180240300360+IL 139West Dundee: 14 mg/LWest Dundee 14Carpentersville: 67 mg/LCarpenters. 67Lake in the Hills: 283 mg/LLake in th. 283Gilberts: 328 mg/LGilberts 328Crystal Lake: 388 mg/LCrystal La. 388Cary: 378 mg/LCary 378378 mg/Loff the scalemg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 378 mg/L, Algonquin is 239 mg/L above the typical Illinois figure of 139. Of the 10 nearest cities we track, 7 have softer water and 2 have harder. The range nearby runs from 14 mg/L in West Dundee to 573 in Lake Barrington.

What 378 mg/L means at home

Scale forms fast here. Kettles and coffee makers need regular descaling, and showerheads clog unless you clean them.

Tank water heaters collect mineral sediment that insulates the water from the burner, so flushing the tank matters more than usual.

Dishes and glass shower doors spot easily. Soap scum and a dull film on hair or laundry are common complaints.

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

At 378 mg/L most of the trouble is scale, and only a few things deal with it.

Ion-exchange water softener

The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.

Salt-free conditioner

No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.

Reverse osmosis or carbon filter

Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.

Softener size for Algonquin

3 people × 75 gallons a day × 22.1 gpg = 4,975 grains a day. A 48,000-grain unit regenerates about every 9 days.

Size it for your household

EPA record for Algonquin's water system

Algonquin · PWSID IL1110050

No health-based violations since 2016

Serves about 30,700 people from groundwater.

Health-based
0
Monitoring or reporting
0
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 Algonquin water hard?

Yes. It measures about 378 mg/L (22.1 grains per gallon), which the USGS classes as very hard.

What is the water hardness in Algonquin in grains per gallon?

About 22.1 gpg. One grain per gallon equals 17.1 mg/L, so 378 mg/L divided by 17.1 gives 22.1.

What size water softener do I need in Algonquin?

For 3 people using 75 gallons each per day, 22.1 gpg works out to about 4,975 grains a day. A 48,000-grain softener covers that with a regeneration about every 9 days.

Has the Algonquin water system had EPA violations?

EPA records show no health-based violations for Algonquin since 2016.

Nearby cities

All 192 cities in Illinois

Hardness data: TapWaterData US Water Hardness (utility report, September 2, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.