Hard water in Ballwin, MO
County estimate from 1,212 water samples in St. Louis County · July 2026
- MO typical
- 121 mg/L
- Softener for 3 people
- 24k grain
- Data
- County estimate
Water samples from around Ballwin put hardness at about 242 mg/L (14.2 gpg), which would be very hard on the USGS scale. Treat this as a rough guide: it is the median of 1,212 samples taken across St. Louis County, mostly wells and streams, not a test of Ballwin's treated tap water.
Ballwin sits 121 mg/L above the typical Missouri figure of 121. Of the 10 nearest cities we track, 9 have softer water and 1 has harder. The range nearby runs from 79 mg/L in Eureka to 263 in Des Peres.
What 242 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 242 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 × 14.2 gpg = 3,184 grains a day. A 24,000-grain unit regenerates about every 7 days.
EPA record for Ballwin's water system
We could not match Ballwin to a community water system in EPA's records. Your water bill or the yearly Consumer Confidence Report names the system and its ID.
Questions
Is Ballwin water hard?
Yes. It measures about 242 mg/L (14.2 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Ballwin in grains per gallon?
About 14.2 gpg. One grain per gallon equals 17.1 mg/L, so 242 mg/L divided by 17.1 gives 14.2.
What size water softener do I need in Ballwin?
For 3 people using 75 gallons each per day, 14.2 gpg works out to about 3,184 grains a day. A 24,000-grain softener covers that with a regeneration about every 7 days.
Nearby cities
- Chesterfield121 mg/LHard
- Town and Country234 mg/LVery hard
- Des Peres263 mg/LVery hard
- Kirkwood130 mg/LHard
- Murphy104 mg/LModerately hard
- Eureka79 mg/LModerately hard
- Ladue155 mg/LHard
- Maryland Heights121 mg/LHard
- Cottleville120 mg/LHard
- St. Peters168 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.