Hard water in Rolla, MO
Calculated from the utility's calcium and magnesium results · December 2020
- MO typical
- 121 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 32k grain
- Data
- Calculated from utility data
The water in Rolla carries roughly 272 mg/L of dissolved calcium and magnesium, or 15.9 grains per gallon. That is very hard water. TapWaterData worked it out from the calcium and magnesium levels the local utility reports (December 2020).
Rolla sits 151 mg/L above the typical Missouri figure of 121. Of the 10 nearest cities we track, 8 have softer water and 2 have harder. The range nearby runs from 188 mg/L in Sullivan to 339 in Bonne Terre.
What 272 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 272 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 × 15.9 gpg = 3,578 grains a day. A 32,000-grain unit regenerates about every 8 days.
EPA record for Rolla's water system
No health-based violations since 2016
Serves about 20,800 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 2
- Open now
- 0
EPA lists this system as serving Rolla.
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 Rolla water hard?
Yes. It measures about 272 mg/L (15.9 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Rolla in grains per gallon?
About 15.9 gpg. One grain per gallon equals 17.1 mg/L, so 272 mg/L divided by 17.1 gives 15.9.
What size water softener do I need in Rolla?
For 3 people using 75 gallons each per day, 15.9 gpg works out to about 3,578 grains a day. A 32,000-grain softener covers that with a regeneration about every 8 days.
Has the Rolla water system had EPA violations?
EPA records show no health-based violations for Rolla PWS since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Fort Leonard Wood216 mg/LVery hard
- Waynesville265 mg/LVery hard
- Sullivan188 mg/LVery hard
- Jefferson City218 mg/LVery hard
- Lebanon210 mg/LVery hard
- Union188 mg/LVery hard
- Washington210 mg/LVery hard
- Fulton289 mg/LVery hard
- Pacific197 mg/LVery hard
- Bonne Terre339 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (calculated from utility data, December 29, 2020), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.