Hard water in Crest Hill, IL

Tap water hardness
465mg/L
27.2gpg
Very hard

Reported by Crest Hill · August 2025

IL typical
139 mg/L
EPA health violations since 2016
1
Softener for 3 people
48k grain
Data
Utility report

Crest Hill water measures 465 mg/L (27.2 gpg) of hardness, very hard by USGS standards. The number comes from Crest Hill, dated August 2025.

Crest Hill on the hardness scale, with nearby cities
060120180240300360+IL typical 139Mokena: 91 mg/LMokena 91Naperville: 120 mg/LNaperville 120Woodridge: 134 mg/LWoodridge 134New Lenox: 137 mg/LNew Lenox 137Lemont: 228 mg/LLemont 228Joliet: 244 mg/LJoliet 244Bolingbrook: 287 mg/LBolingbrook 287Homer Glen: 287 mg/LHomer Glen 287Romeoville: 303 mg/LRomeoville 303Lockport: 458 mg/LLockport 458Crest Hill 465off the scalemg/L as calcium carbonate060120180240300360+IL 139New Lenox: 137 mg/LNew Lenox 137Joliet: 244 mg/LJoliet 244Bolingbrook: 287 mg/LBolingbrook 287Homer Glen: 287 mg/LHomer Glen 287Romeoville: 303 mg/LRomeoville 303Lockport: 458 mg/LLockport 458465 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

Crest Hill sits 326 mg/L above the typical Illinois figure of 139. None of the 10 nearest cities we track has harder water. The range nearby runs from 91 mg/L in Mokena to 458 in Lockport.

What 465 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 465 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 Crest Hill

3 people × 75 gallons a day × 27.2 gpg = 6,118 grains a day. A 48,000-grain unit regenerates about every 7 days.

Size it for your household

EPA record for Crest Hill's water system

Crest Hill · PWSID IL1970250

1 health-based violation since 2016

Serves about 20,223 people from groundwater.

Health-based
1
Monitoring or reporting
47
Open now
3
20162017201820192020202120222023202420252026Lead and Copper Rule'16'18'20'22'24'26Lead and Copper Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Lead and Copper Rulecorrosion control and lead sampling12024Resolved

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 Crest Hill water hard?

Yes. It measures about 465 mg/L (27.2 grains per gallon), which the USGS classes as very hard.

What is the water hardness in Crest Hill in grains per gallon?

About 27.2 gpg. One grain per gallon equals 17.1 mg/L, so 465 mg/L divided by 17.1 gives 27.2.

What size water softener do I need in Crest Hill?

For 3 people using 75 gallons each per day, 27.2 gpg works out to about 6,118 grains a day. A 48,000-grain softener covers that with a regeneration about every 7 days.

Has the Crest Hill water system had EPA violations?

EPA records show 1 health-based violation for Crest Hill since 2016, involving Lead and Copper Rule. There were also 47 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, August 11, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.