Hard water in Sidney, MT

Tap water hardness
491mg/L
28.7gpg
Very hard

Calculated from the utility's calcium and magnesium results · June 2025

MT typical
116 mg/L
EPA health violations since 2016
0
Softener for 3 people
48k grain
Data
Calculated from utility data

The water in Sidney carries roughly 491 mg/L of dissolved calcium and magnesium, or 28.7 grains per gallon. That is very hard water. TapWaterData worked it out from the calcium and magnesium levels the local utility reports (June 2025).

Sidney on the hardness scale, with nearby cities
060120180240300360+MT typical 116Kalispell: 73 mg/LKalispell 73Bozeman: 92 mg/LBozeman 92Butte: 97 mg/LButte 97Missoula: 116 mg/LMissoula 116Orchard Homes: 116 mg/LOrchard Homes 116Great Falls: 145 mg/LGreat Falls 145Billings: 159 mg/LBillings 159Belgrade: 226 mg/LBelgrade 226Sidney 491off the scalemg/L as calcium carbonate060120180240300360+MT 116Bozeman: 92 mg/LBozeman 92Butte: 97 mg/LButte 97Missoula: 116 mg/LMissoula 116Great Falls: 145 mg/LGreat Falls 145Billings: 159 mg/LBillings 159Belgrade: 226 mg/LBelgrade 226491 mg/Loff the scalemg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Sidney sits 375 mg/L above the typical Montana figure of 116. None of the 8 nearest cities we track has harder water. The range nearby runs from 73 mg/L in Kalispell to 226 in Belgrade.

What 491 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 491 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 Sidney

3 people × 75 gallons a day × 28.7 gpg = 6,455 grains a day. A 48,000-grain unit regenerates about every 7 days.

Size it for your household

EPA record for Sidney's water system

Sidney City of · PWSID MT0000330

No health-based violations since 2016

Serves about 5,000 people from groundwater.

Health-based
0
Monitoring or reporting
0
Open now
0

EPA lists this system as serving Sidney.

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 Sidney water hard?

Yes. It measures about 491 mg/L (28.7 grains per gallon), which the USGS classes as very hard.

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

About 28.7 gpg. One grain per gallon equals 17.1 mg/L, so 491 mg/L divided by 17.1 gives 28.7.

What size water softener do I need in Sidney?

For 3 people using 75 gallons each per day, 28.7 gpg works out to about 6,455 grains a day. A 48,000-grain softener covers that with a regeneration about every 7 days.

Has the Sidney water system had EPA violations?

EPA records show no health-based violations for Sidney City of since 2016.

Nearby cities

All 9 cities in Montana

Hardness data: TapWaterData US Water Hardness (calculated from utility data, June 16, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.