Hard water in Franklin, WI
County estimate from 13,893 water samples in Milwaukee County · July 2026
- WI typical
- 170 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- County estimate
Water samples from around Franklin put hardness at about 210 mg/L (12.3 gpg), which would be very hard on the USGS scale. Treat this as a rough guide: it is the median of 13,893 samples taken across Milwaukee County, mostly wells and streams, not a test of Franklin's treated tap water. One more reason for caution: EPA lists Franklin's water system as using surface water, which is often softer than the wells behind the county figure.
At 210 mg/L, Franklin is 40 mg/L above the typical Wisconsin figure of 170. Of the 10 nearest cities we track, 5 have softer water and 3 have harder. The range nearby runs from 134 mg/L in Wauwatosa to 330 in New Berlin.
What 210 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 210 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 × 12.3 gpg = 2,763 grains a day. A 24,000-grain unit regenerates about every 8 days.
EPA record for Franklin's water system
No health-based violations since 2016
Serves about 22,500 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 2
- Open now
- 1
EPA lists this system as serving Franklin.
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 Franklin water hard?
Yes. It measures about 210 mg/L (12.3 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Franklin in grains per gallon?
About 12.3 gpg. One grain per gallon equals 17.1 mg/L, so 210 mg/L divided by 17.1 gives 12.3.
What size water softener do I need in Franklin?
For 3 people using 75 gallons each per day, 12.3 gpg works out to about 2,763 grains a day. A 24,000-grain softener covers that with a regeneration about every 8 days.
Has the Franklin water system had EPA violations?
EPA records show no health-based violations for Franklin Water Utility since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Greenfield135 mg/LHard
- Oak Creek210 mg/LVery hard
- Muskego276 mg/LVery hard
- South Milwaukee210 mg/LVery hard
- New Berlin330 mg/LVery hard
- West Allis135 mg/LHard
- Cudahy142 mg/LHard
- Caledonia300 mg/LVery hard
- St. Francis135 mg/LHard
- Wauwatosa134 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.