How hard is the water in Blaine County, MT?
17 grains per gallon
A softener will pay its way here.
The median hardness measured in Blaine County, MT is 291 mg/L as calcium carbonate, which is 17 gpg. That is very hard on the USGS scale. It comes from 177 samples at 30 sites between 1990 and 2026, drawn from groundwater wells, which is what most taps and private wells in the county draw on.
How much it varies here
Half the sites came in between 11 and 22.9 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 17 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 0.5 to 70.7 gpg
The softest single sample on record in Blaine County was 8.3 mg/L and the hardest 1,210 mg/L, a 146-fold gap. The top quarter of sites read above 22.9 gpg and the bottom quarter below 11 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 17 gpg, rivers and lakes 16.2 gpg
177 groundwater samples from 30 wells put the median at 291.3 mg/L. 969 surface samples from 64 sites put it at 277 mg/L. In Blaine County the wells come out 0.8 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 372 lb of salt a year (10 bags of 40 lb, about $67), 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 $167 a year.
Sizing at 17 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,020 | 24,000 | 124 lb |
| 2 | 2,040 | 24,000 | 248 lb |
| 4 | 4,080 | 32,000 | 496 lb |
| 6 | 6,120 | 48,000 | 745 lb |
Blaine County against the rest of Montana
Among the 56 Montana counties with data, Blaine County is number 26 of 56 counting from the hardest. Across the whole country it is harder than 76% of counties.
Softest in Montana: Lincoln County at 3.4 gpg. Hardest: Rosebud County at 138.9 gpg. Closest to Blaine County: Custer County (16.8), Daniels County (16), Wheatland County (18).