Hard water in Downers Grove, IL

Tap water hardness
131mg/L
7.7gpg
Hard

Reported by Downers Grove · July 2025

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

Downers Grove water measures 131 mg/L (7.7 gpg) of hardness, hard by USGS standards. The number comes from Downers Grove, dated July 2025.

Downers Grove on the hardness scale, with nearby cities
060120180240300360+IL typical 139Villa Park: 99 mg/LVilla Park 99Wheaton: 124 mg/LWheaton 124Westmont: 127 mg/LWestmont 127Hinsdale: 133 mg/LHinsdale 133Woodridge: 134 mg/LWoodridge 134Glen Ellyn: 136 mg/LGlen Ellyn 136Clarendon Hills: 159 mg/LClarendon Hills 159Lisle: 287 mg/LLisle 287Darien: 287 mg/LDarien 287Lombard: 287 mg/LLombard 287Downers Grove 131mg/L as calcium carbonate060120180240300360+IL 139Westmont: 127 mg/LWestmont 127Hinsdale: 133 mg/LHinsdale 133Woodridge: 134 mg/LWoodridge 134Clarendon Hills: 159 mg/LClarendon. 159Lisle: 287 mg/LLisle 287Darien: 287 mg/LDarien 287131 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 131 mg/L, Downers Grove is close to the typical Illinois figure of 139 mg/L. Of the 10 nearest cities we track, 3 have softer water and 7 have harder. The range nearby runs from 99 mg/L in Villa Park to 287 in Lisle.

What 131 mg/L means at home

Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.

Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.

Soap and detergent need a little more to lather, and soap scum shows up in the tub.

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 131 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 Downers Grove

3 people × 75 gallons a day × 7.7 gpg = 1,724 grains a day. A 24,000-grain unit regenerates about every 13 days.

Size it for your household

EPA record for Downers Grove's water system

Downers Grove · PWSID IL0430300

No health-based violations since 2016

Serves about 49,425 people from surface water.

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 Downers Grove water hard?

Yes. It measures about 131 mg/L (7.7 grains per gallon), which the USGS classes as hard.

What is the water hardness in Downers Grove in grains per gallon?

About 7.7 gpg. One grain per gallon equals 17.1 mg/L, so 131 mg/L divided by 17.1 gives 7.7.

What size water softener do I need in Downers Grove?

For 3 people using 75 gallons each per day, 7.7 gpg works out to about 1,724 grains a day. A 24,000-grain softener covers that with a regeneration about every 13 days.

Has the Downers Grove water system had EPA violations?

EPA records show no health-based violations for Downers Grove 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, July 21, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.