Hard water in Minnetonka, MN
Reported by Minnetonka · May 2025
- MN typical
- 160 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Minnetonka carries roughly 186 mg/L of dissolved calcium and magnesium, or 10.9 grains per gallon. That is very hard water. The number comes from Minnetonka, dated May 2025.
At 186 mg/L, Minnetonka is 26 mg/L above the typical Minnesota figure of 160. Of the 10 nearest cities we track, 8 have softer water and 2 have harder. The range nearby runs from 89 mg/L in Minneapolis to 230 in Chaska.
What 186 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 186 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 × 10.9 gpg = 2,448 grains a day. A 24,000-grain unit regenerates about every 9 days.
EPA record for Minnetonka's water system
No health-based violations since 2016
Serves about 54,474 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 0
- 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 Minnetonka water hard?
Yes. It measures about 186 mg/L (10.9 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Minnetonka in grains per gallon?
About 10.9 gpg. One grain per gallon equals 17.1 mg/L, so 186 mg/L divided by 17.1 gives 10.9.
What size water softener do I need in Minnetonka?
For 3 people using 75 gallons each per day, 10.9 gpg works out to about 2,448 grains a day. A 24,000-grain softener covers that with a regeneration about every 9 days.
Has the Minnetonka water system had EPA violations?
EPA records show no health-based violations for Minnetonka since 2016.
Nearby cities
- Hopkins163 mg/LHard
- St. Louis Park112 mg/LModerately hard
- Edina146 mg/LHard
- Eden Prairie99 mg/LModerately hard
- Golden Valley90 mg/LModerately hard
- Chanhassen121 mg/LHard
- Robbinsdale201 mg/LVery hard
- Minneapolis89 mg/LModerately hard
- Bloomington100 mg/LModerately hard
- Chaska230 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (utility report, May 7, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.