Hard water in Middleton, WI

Tap water hardness
337mg/L
19.7gpg
Very hard

Reported by Middleton Waterworks · August 2025

WI typical
170 mg/L
EPA health violations since 2016
1
Softener for 3 people
32k grain
Data
Utility report

Tap water in Middleton has about 337 mg/L of hardness, which is 19.7 grains per gallon. On the USGS scale that counts as very hard. The number comes from Middleton Waterworks, dated August 2025.

Middleton on the hardness scale, with nearby cities
060120180240300360+WI typical 170Fitchburg: 270 mg/LFitchburg 270DeForest: 280 mg/LDeForest 280Waunakee: 282 mg/LWaunakee 282Oregon: 283 mg/LOregon 283Sun Prairie: 337 mg/LSun Prairie 337Madison: 341 mg/LMadison 341Cottage Grove: 347 mg/LCottage Grove 347Verona: 360 mg/LVerona 360Monona: 420 mg/LMonona 420McFarland: 364 mg/LMcFarland 364Middleton 337mg/L as calcium carbonate060120180240300360+WI 170Fitchburg: 270 mg/LFitchburg 270DeForest: 280 mg/LDeForest 280Waunakee: 282 mg/LWaunakee 282Madison: 341 mg/LMadison 341Verona: 360 mg/LVerona 360Monona: 420 mg/LMonona 420337 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 337 mg/L, Middleton is 167 mg/L above the typical Wisconsin figure of 170. Of the 10 nearest cities we track, 4 have softer water and 5 have harder. The range nearby runs from 270 mg/L in Fitchburg to 420 in Monona.

What 337 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 337 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.

Softener size for Middleton

3 people × 75 gallons a day × 19.7 gpg = 4,435 grains a day. A 32,000-grain unit regenerates about every 7 days.

Size it for your household

EPA record for Middleton's water system

Middleton Waterworks · PWSID WI1130242

1 health-based violation since 2016

Serves about 23,868 people from groundwater.

Health-based
1
Monitoring or reporting
29
Open now
2
20162017201820192020202120222023202420252026Lead and Copper Rule'16'18'20'22'24'26Lead and Copper Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Lead and Copper Rulecorrosion control and lead sampling12024Resolved

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 Middleton water hard?

Yes. It measures about 337 mg/L (19.7 grains per gallon), which the USGS classes as very hard.

What is the water hardness in Middleton in grains per gallon?

About 19.7 gpg. One grain per gallon equals 17.1 mg/L, so 337 mg/L divided by 17.1 gives 19.7.

What size water softener do I need in Middleton?

For 3 people using 75 gallons each per day, 19.7 gpg works out to about 4,435 grains a day. A 32,000-grain softener covers that with a regeneration about every 7 days.

Has the Middleton water system had EPA violations?

EPA records show 1 health-based violation for Middleton Waterworks since 2016, involving Lead and Copper Rule. There were also 29 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 112 cities in Wisconsin

Hardness data: TapWaterData US Water Hardness (utility report, August 17, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.