Hard water in St. Louis, MI
Reported by ST. Louis, City of · May 2022
- MI typical
- 112 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Tap water in St. Louis has about 255 mg/L of hardness, which is 14.9 grains per gallon. On the USGS scale that counts as very hard. The number comes from ST. Louis, City of, dated May 2022.
St. Louis sits 143 mg/L above the typical Michigan figure of 112. Of the 10 nearest cities we track, 4 have softer water and 6 have harder. The range nearby runs from 113 mg/L in Flushing to 458 in Grand Ledge.
What 255 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 255 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 × 14.9 gpg = 3,355 grains a day. A 24,000-grain unit regenerates about every 7 days.
EPA record for St. Louis's water system
No health-based violations since 2016
Serves about 6,976 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 1
- 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 St. Louis water hard?
Yes. It measures about 255 mg/L (14.9 grains per gallon), which the USGS classes as very hard.
What is the water hardness in St. Louis in grains per gallon?
About 14.9 gpg. One grain per gallon equals 17.1 mg/L, so 255 mg/L divided by 17.1 gives 14.9.
What size water softener do I need in St. Louis?
For 3 people using 75 gallons each per day, 14.9 gpg works out to about 3,355 grains a day. A 24,000-grain softener covers that with a regeneration about every 7 days.
Has the St. Louis water system had EPA violations?
EPA records show no health-based violations for ST. Louis, City of since 2016. There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.
Nearby cities
- Mount Pleasant225 mg/LVery hard
- Greenville346 mg/LVery hard
- Owosso339 mg/LVery hard
- Ionia395 mg/LVery hard
- Belding269 mg/LVery hard
- Bay City128 mg/LHard
- Flushing113 mg/LModerately hard
- Grand Ledge458 mg/LVery hard
- East Lansing194 mg/LVery hard
- Waverly458 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (utility report, May 31, 2022), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.