How hard is the water in Powder River County, MT?
60.8 grains per gallon
A softener will pay its way here.
The median hardness measured in Powder River County, MT is 1040 mg/L as calcium carbonate, which is 60.8 gpg. That is very hard on the USGS scale. It comes from 563 samples at 29 sites between 2001 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 35.1 and 71.9 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 60.8 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 7.0 to 158.3 gpg
The softest single sample on record in Powder River County was 120 mg/L and the hardest 2,710 mg/L, a 23-fold gap. The top quarter of sites read above 71.9 gpg and the bottom quarter below 35.1 gpg.
What a softener would cost to run
For a household of 3, a 80,000-grain unit covers a week between regenerations. Expect about 1,327 lb of salt a year (34 bags of 40 lb, about $239), 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 $339 a year.
Sizing at 60.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 3,648 | 32,000 | 444 lb |
| 2 | 7,296 | 64,000 | 888 lb |
| 4 | 14,592 | twin tank | 1,775 lb |
| 6 | 21,888 | twin tank | 2,663 lb |
Powder River County against the rest of Montana
Among the 56 Montana counties with data, Powder River County is number 4 of 56 counting from the hardest. Across the whole country it is harder than 98% of counties.
Softest in Montana: Lincoln County at 3.4 gpg. Hardest: Rosebud County at 138.9 gpg. Closest to Powder River County: Cascade County (58.6), Liberty County (67.8), Petroleum County (50.9).