How hard is the water in Fallon County, MT?
25.8 grains per gallon
A softener will pay its way here.
The median hardness measured in Fallon County, MT is 441 mg/L as calcium carbonate, which is 25.8 gpg. That is very hard on the USGS scale. It comes from 170 samples at 37 sites between 1990 and 2026, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 16.2 and 48.3 gpg. The whole middle of that range gives the same answer, so a test of your own tap is unlikely to change it. Confidence in the county figure: high (how it is measured).
What to do next
At 25.8 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water.
More on sizing a softener for your household.
From 3.5 to 175.0 gpg
The softest single sample on record in Fallon County was 59.5 mg/L and the hardest 2,995 mg/L, a 50-fold gap. The top quarter of sites read above 48.3 gpg and the bottom quarter below 16.2 gpg. So even here some sites draw water soft enough to need nothing at all.
What a softener would cost to run
For a household of 3, a 40,000-grain unit covers a week between regenerations. Expect about 563 lb of salt a year (15 bags of 40 lb, about $101), and roughly 2,346 gallons of regeneration water. Installed, most units run $1,000 to $4,500; spread over 15 years with salt, that is about $201 a year.
Sizing at 25.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,548 | 24,000 | 188 lb |
| 2 | 3,096 | 24,000 | 377 lb |
| 4 | 6,192 | 48,000 | 753 lb |
| 6 | 9,288 | 80,000 | 1,130 lb |
Fallon County against the rest of Montana
Among the 56 Montana counties with data, Fallon County is number 17 of 56 counting from the hardest. Across the whole country it is harder than 92% of counties.
Softest in Montana: Lincoln County at 3.4 gpg. Hardest: Rosebud County at 138.9 gpg. Closest to Fallon County: Prairie County (24.4), Phillips County (24.2), Carter County (24).