Hard water in Green Bay, WI
Reported by Green Bay Waterworks · August 2022
- WI typical
- 170 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Green Bay carries roughly 137 mg/L of dissolved calcium and magnesium, or 8.0 grains per gallon. That is hard water. The number comes from Green Bay Waterworks, dated August 2022. Reports for this system disagree, with values from 87 to 137 mg/L.
At 137 mg/L, Green Bay is 33 mg/L below the typical Wisconsin figure of 170. Of the 10 nearest cities we track, 5 have softer water and 5 have harder. The range nearby runs from 73 mg/L in Kimberly to 196 in Suamico.
What 137 mg/L means at home
Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.
Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.
Soap and detergent need a little more to lather, and soap scum shows up in the tub.
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 137 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 × 8.0 gpg = 1,802 grains a day. A 24,000-grain unit regenerates about every 13 days.
EPA record for Green Bay's water system
No health-based violations since 2016
Serves about 107,369 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 4
- 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 Green Bay water hard?
Yes. It measures about 137 mg/L (8.0 grains per gallon), which the USGS classes as hard.
What is the water hardness in Green Bay in grains per gallon?
About 8.0 gpg. One grain per gallon equals 17.1 mg/L, so 137 mg/L divided by 17.1 gives 8.0.
What size water softener do I need in Green Bay?
For 3 people using 75 gallons each per day, 8.0 gpg works out to about 1,802 grains a day. A 24,000-grain softener covers that with a regeneration about every 13 days.
Has the Green Bay water system had EPA violations?
EPA records show no health-based violations for Green Bay Waterworks since 2016. There were also 4 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Allouez136 mg/LHard
- Suamico196 mg/LVery hard
- De Pere194 mg/LVery hard
- Little Chute87 mg/LModerately hard
- Kimberly73 mg/LModerately hard
- Appleton81 mg/LModerately hard
- Menasha166 mg/LHard
- Fox Crossing166 mg/LHard
- Greenville152 mg/LHard
- Two Rivers136 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, August 16, 2022), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.