Hard water in Frankfort, IL
County estimate from 1,321 water samples in Will County · July 2026
- IL typical
- 139 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 32k grain
- Data
- County estimate
Water samples from around Frankfort put hardness at about 287 mg/L (16.8 gpg), which would be very hard on the USGS scale. Treat this as a rough guide: it is the median of 1,321 samples taken across Will County, mostly wells and streams, not a test of Frankfort's treated tap water.
Frankfort sits 148 mg/L above the typical Illinois figure of 139. Of the 10 nearest cities we track, 6 have softer water and 3 have harder. The range nearby runs from 91 mg/L in Mokena to 558 in Monee.
What 287 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 287 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.
3 people × 75 gallons a day × 16.8 gpg = 3,776 grains a day. A 32,000-grain unit regenerates about every 8 days.
EPA record for Frankfort's water system
No health-based violations since 2016
Serves about 24,000 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 16
- Open now
- 1
EPA lists this system as serving Frankfort.
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 Frankfort water hard?
Yes. It measures about 287 mg/L (16.8 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Frankfort in grains per gallon?
About 16.8 gpg. One grain per gallon equals 17.1 mg/L, so 287 mg/L divided by 17.1 gives 16.8.
What size water softener do I need in Frankfort?
For 3 people using 75 gallons each per day, 16.8 gpg works out to about 3,776 grains a day. A 32,000-grain softener covers that with a regeneration about every 8 days.
Has the Frankfort water system had EPA violations?
EPA records show no health-based violations for Frankfort since 2016. There were also 16 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Mokena91 mg/LModerately hard
- New Lenox137 mg/LHard
- Tinley Park300 mg/LVery hard
- Orland Hills147 mg/LHard
- Richton Park206 mg/LVery hard
- Orland Park147 mg/LHard
- Homer Glen287 mg/LVery hard
- Manhattan372 mg/LVery hard
- Monee558 mg/LVery hard
- Park Forest163 mg/LHard
Hardness data: TapWaterData US Water Hardness (county estimate, July 4, 2026), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.