How hard is the water in Chouteau County, MT?
11.4 grains per gallon
A softener will pay its way here.
The median hardness measured in Chouteau County, MT is 196 mg/L as calcium carbonate, which is 11.4 gpg. That is very hard on the USGS scale. It comes from 274 samples at 38 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 8.5 and 15.7 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: high (how it is measured).
What to do next
At 11.4 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. Because Chouteau County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on sizing a softener for your household.
From 6.1 to 146.6 gpg
The softest single sample on record in Chouteau County was 104 mg/L and the hardest 2,510 mg/L, a 24-fold gap. The top quarter of sites read above 15.7 gpg and the bottom quarter below 8.5 gpg.
Wells 146.6 gpg, rivers and lakes 11.7 gpg
1 groundwater samples from 1 wells put the median at 2510 mg/L. 270 surface samples from 34 sites put it at 200 mg/L. In Chouteau County the wells come out 134.9 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 249 lb of salt a year (7 bags of 40 lb, about $45), 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 $145 a year.
Sizing at 11.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 684 | 24,000 | 83 lb |
| 2 | 1,368 | 24,000 | 166 lb |
| 4 | 2,736 | 24,000 | 333 lb |
| 6 | 4,104 | 32,000 | 499 lb |
Chouteau County against the rest of Montana
Among the 56 Montana counties with data, Chouteau County is number 39 of 56 counting from the hardest. Across the whole country it is harder than 56% of counties.
Softest in Montana: Lincoln County at 3.4 gpg. Hardest: Rosebud County at 138.9 gpg. Closest to Chouteau County: Gallatin County (11.4), Flathead County (11), Madison County (10.7).