Hard water in Mequon, WI
Reported by Mequon Water Utility · August 2022
- WI typical
- 170 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 48k grain
- Data
- Utility report
Tap water in Mequon has about 440 mg/L of hardness, which is 25.7 grains per gallon. On the USGS scale that counts as very hard. The number comes from Mequon Water Utility, dated August 2022. Reports for this system disagree, with values from 250 to 440 mg/L.
At 440 mg/L, Mequon is 270 mg/L above the typical Wisconsin figure of 170. None of the 10 nearest cities we track has harder water. The range nearby runs from 129 mg/L in Whitefish Bay to 422 in Germantown.
What 440 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 440 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 × 25.7 gpg = 5,792 grains a day. A 48,000-grain unit regenerates about every 8 days.
EPA record for Mequon's water system
No health-based violations since 2016
Serves about 11,152 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 2
- 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 Mequon water hard?
Yes. It measures about 440 mg/L (25.7 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Mequon in grains per gallon?
About 25.7 gpg. One grain per gallon equals 17.1 mg/L, so 440 mg/L divided by 17.1 gives 25.7.
What size water softener do I need in Mequon?
For 3 people using 75 gallons each per day, 25.7 gpg works out to about 5,792 grains a day. A 48,000-grain softener covers that with a regeneration about every 8 days.
Has the Mequon water system had EPA violations?
EPA records show no health-based violations for Mequon Water Utility since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Germantown422 mg/LVery hard
- Cedarburg400 mg/LVery hard
- Menomonee Falls174 mg/LHard
- Fox Point133 mg/LHard
- Glendale134 mg/LHard
- Grafton370 mg/LVery hard
- Whitefish Bay129 mg/LHard
- Wauwatosa134 mg/LHard
- Milwaukee135 mg/LHard
- Shorewood130 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, August 15, 2022), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.