How hard is the water in Deer Lodge County, MT?
8.9 grains per gallon
A softener is worth it here.
The median hardness measured in Deer Lodge County, MT is 153 mg/L as calcium carbonate, which is 8.9 gpg. That is hard on the USGS scale. It comes from 126 samples at 11 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 7.1 and 13.4 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 8.9 gpg a softener is worth getting, mainly to protect the water heater and cut soap use. Get at least two quotes, ask each installer what grain capacity they are fitting, and check it against the sizing table below. Because Deer Lodge 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 3.2 to 17.5 gpg
The softest single sample on record in Deer Lodge County was 54.5 mg/L and the hardest 300 mg/L, a 6-fold gap. The top quarter of sites read above 13.4 gpg and the bottom quarter below 7.1 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 8.9 gpg, rivers and lakes 6 gpg
126 groundwater samples from 11 wells put the median at 153 mg/L. 3,362 surface samples from 118 sites put it at 103.5 mg/L. In Deer Lodge County the wells come out 2.9 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. 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 195 lb of salt a year (5 bags of 40 lb, about $35), 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 $135 a year.
Sizing at 8.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 534 | 24,000 | 65 lb |
| 2 | 1,068 | 24,000 | 130 lb |
| 4 | 2,136 | 24,000 | 260 lb |
| 6 | 3,204 | 24,000 | 390 lb |
Deer Lodge County against the rest of Montana
Among the 56 Montana counties with data, Deer Lodge County is number 44 of 56 counting from the hardest. Across the whole country it is harder than 46% of counties.
Softest in Montana: Lincoln County at 3.4 gpg. Hardest: Rosebud County at 138.9 gpg. Closest to Deer Lodge County: Hill County (8.7), Granite County (9.2), Missoula County (8.4).