Hard water in Casper, WY
Reported by Casper, City of · April 2025
- WY typical
- 191 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 32k grain
- Data
- Utility report
The water in Casper carries roughly 327 mg/L of dissolved calcium and magnesium, or 19.1 grains per gallon. That is very hard water. The number comes from Casper, City of, dated April 2025.
At 327 mg/L, Casper is 136 mg/L above the typical Wyoming figure of 191. Of the 5 nearest cities we track, 4 have softer water and 1 has harder. The range nearby runs from 27 mg/L in Sheridan to 926 in Gillette.
What 327 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 327 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 × 19.1 gpg = 4,302 grains a day. A 32,000-grain unit regenerates about every 7 days.
EPA record for Casper's water system
No health-based violations since 2016
Serves about 59,000 people from surface water.
- 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 Casper water hard?
Yes. It measures about 327 mg/L (19.1 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Casper in grains per gallon?
About 19.1 gpg. One grain per gallon equals 17.1 mg/L, so 327 mg/L divided by 17.1 gives 19.1.
What size water softener do I need in Casper?
For 3 people using 75 gallons each per day, 19.1 gpg works out to about 4,302 grains a day. A 32,000-grain softener covers that with a regeneration about every 7 days.
Has the Casper water system had EPA violations?
EPA records show no health-based violations for Casper, City of since 2016.
Nearby cities
- Gillette926 mg/LVery hard
- Sheridan27 mg/LSoft
- Cheyenne49 mg/LSoft
- Rock Springs210 mg/LVery hard
- Jackson163 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, April 15, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.