How hard is the water in Cascade County, MT?
58.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Cascade County, MT is 1003 mg/L as calcium carbonate, which is 58.6 gpg. That is very hard on the USGS scale. It comes from 311 samples at 18 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 29.6 and 91.4 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 58.6 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 6.0 to 231.3 gpg
The softest single sample on record in Cascade County was 103 mg/L and the hardest 3,960 mg/L, a 38-fold gap. The top quarter of sites read above 91.4 gpg and the bottom quarter below 29.6 gpg.
Wells 58.6 gpg, rivers and lakes 10.4 gpg
311 groundwater samples from 18 wells put the median at 1003 mg/L. 1,107 surface samples from 86 sites put it at 178.8 mg/L. In Cascade County the wells come out 48.2 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 80,000-grain unit covers a week between regenerations. Expect about 1,280 lb of salt a year (32 bags of 40 lb, about $230), 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 $330 a year.
Sizing at 58.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 3,516 | 32,000 | 428 lb |
| 2 | 7,032 | 64,000 | 856 lb |
| 4 | 14,064 | twin tank | 1,711 lb |
| 6 | 21,096 | twin tank | 2,567 lb |
Cascade County against the rest of Montana
Among the 56 Montana counties with data, Cascade County is number 5 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 Cascade County: Powder River County (60.8), Petroleum County (50.9), Roosevelt County (49.5).