Hard water in Great Falls, MT
Calculated from the utility's calcium and magnesium results · October 2024
- MT typical
- 116 mg/L
- EPA health violations since 2016
- 5
- Softener for 3 people
- 24k grain
- Data
- Calculated from utility data
Great Falls water measures 145 mg/L (8.5 gpg) of hardness, hard by USGS standards. TapWaterData worked it out from the calcium and magnesium levels the local utility reports (October 2024).
At 145 mg/L, Great Falls is 29 mg/L above the typical Montana figure of 116. Of the 8 nearest cities we track, 5 have softer water and 3 have harder. The range nearby runs from 73 mg/L in Kalispell to 491 in Sidney.
What 145 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 145 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 × 8.5 gpg = 1,904 grains a day. A 24,000-grain unit regenerates about every 12 days.
EPA record for Great Falls's water system
5 health-based violations since 2016
Serves about 60,000 people from surface water.
- Health-based
- 5
- Monitoring or reporting
- 0
- Open now
- 0
EPA lists this system as serving Great Falls.
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Haloacetic acids (HAA5)a disinfection byproduct | 5 | 2018–2019 | Resolved |
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 Great Falls water hard?
Yes. It measures about 145 mg/L (8.5 grains per gallon), which the USGS classes as hard.
What is the water hardness in Great Falls in grains per gallon?
About 8.5 gpg. One grain per gallon equals 17.1 mg/L, so 145 mg/L divided by 17.1 gives 8.5.
What size water softener do I need in Great Falls?
For 3 people using 75 gallons each per day, 8.5 gpg works out to about 1,904 grains a day. A 24,000-grain softener covers that with a regeneration about every 12 days.
Has the Great Falls water system had EPA violations?
EPA records show 5 health-based violations for Great Falls City of since 2016, involving Haloacetic acids (HAA5).
Nearby cities
- Belgrade226 mg/LVery hard
- Bozeman92 mg/LModerately hard
- Butte97 mg/LModerately hard
- Missoula116 mg/LModerately hard
- Orchard Homes116 mg/LModerately hard
- Kalispell73 mg/LModerately hard
- Billings159 mg/LHard
- Sidney491 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (calculated from utility data, October 28, 2024), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.