Hard water in St. John, IN
County estimate from 921 water samples in Lake County · July 2026
- IN typical
- 178 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- County estimate
Water samples from around St. John put hardness at about 210 mg/L (12.3 gpg), which would be very hard on the USGS scale. Treat this as a rough guide: it is the median of 921 samples taken across Lake County, mostly wells and streams, not a test of St. John's treated tap water.
At 210 mg/L, St. John is 32 mg/L above the typical Indiana figure of 178. None of the 10 nearest cities we track has harder water. The range nearby runs from 134 mg/L in Highland to 210 in Schererville.
What 210 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 210 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 × 12.3 gpg = 2,763 grains a day. A 24,000-grain unit regenerates about every 8 days.
EPA record for St. John's water system
No health-based violations since 2016
Serves about 25,700 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 0
- Open now
- 0
EPA lists this system as serving St. John.
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 St. John water hard?
Yes. It measures about 210 mg/L (12.3 grains per gallon), which the USGS classes as very hard.
What is the water hardness in St. John in grains per gallon?
About 12.3 gpg. One grain per gallon equals 17.1 mg/L, so 210 mg/L divided by 17.1 gives 12.3.
What size water softener do I need in St. John?
For 3 people using 75 gallons each per day, 12.3 gpg works out to about 2,763 grains a day. A 24,000-grain softener covers that with a regeneration about every 8 days.
Has the St. John water system had EPA violations?
EPA records show no health-based violations for ST. John Municipal Water Utility since 2016.
Nearby cities
- Schererville210 mg/LVery hard
- Dyer158 mg/LHard
- Crown Point210 mg/LVery hard
- Highland134 mg/LHard
- Munster210 mg/LVery hard
- Merrillville210 mg/LVery hard
- Hobart210 mg/LVery hard
- Gary210 mg/LVery hard
- Hammond210 mg/LVery hard
- East Chicago135 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.