How hard is the water in Butte County, SD?
48.5 grains per gallon
A softener will pay its way here.
The median hardness measured in Butte County, SD is 831 mg/L as calcium carbonate, which is 48.5 gpg. That is very hard on the USGS scale. It comes from 547 samples at 24 sites between 1990 and 2023, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 39.1 and 54.7 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 48.5 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 1.9 to 118.6 gpg
The softest single sample on record in Butte County was 32 mg/L and the hardest 2,030 mg/L, a 63-fold gap. The top quarter of sites read above 54.7 gpg and the bottom quarter below 39.1 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 18.3 gpg, rivers and lakes 51.6 gpg
3 groundwater samples from 3 wells put the median at 314 mg/L. 544 surface samples from 21 sites put it at 883 mg/L. In Butte County the rivers and lakes come out 33.3 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. A utility here that draws from the aquifer can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 64,000-grain unit covers a week between regenerations. Expect about 1,060 lb of salt a year (27 bags of 40 lb, about $191), 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 $291 a year.
Sizing at 48.5 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 2,910 | 24,000 | 354 lb |
| 2 | 5,820 | 48,000 | 708 lb |
| 4 | 11,640 | twin tank | 1,416 lb |
| 6 | 17,460 | twin tank | 2,124 lb |
Butte County against the rest of South Dakota
Among the 55 South Dakota counties with data, Butte County is number 7 of 55 counting from the hardest. Across the whole country it is harder than 98% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Butte County: Lincoln County (47.9), Charles Mix County (49.2), McCook County (46.6).