How hard is the water in Charles Mix County, SD?
49.2 grains per gallon
A softener will pay its way here.
The median hardness measured in Charles Mix County, SD is 842 mg/L as calcium carbonate, which is 49.2 gpg. That is very hard on the USGS scale. It comes from 667 samples at 42 sites between 1990 and 2022, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 35.7 and 67 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 49.2 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 5.9 to 174.1 gpg
The softest single sample on record in Charles Mix County was 101 mg/L and the hardest 2,980 mg/L, a 30-fold gap. The top quarter of sites read above 67 gpg and the bottom quarter below 35.7 gpg.
Wells 21.4 gpg, rivers and lakes 54.2 gpg
3 groundwater samples from 3 wells put the median at 367 mg/L. 664 surface samples from 39 sites put it at 927 mg/L. In Charles Mix County the rivers and lakes come out 32.8 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 1,074 lb of salt a year (27 bags of 40 lb, about $193), 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 $293 a year.
Sizing at 49.2 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 2,952 | 24,000 | 359 lb |
| 2 | 5,904 | 48,000 | 718 lb |
| 4 | 11,808 | twin tank | 1,437 lb |
| 6 | 17,712 | twin tank | 2,155 lb |
Charles Mix County against the rest of South Dakota
Among the 55 South Dakota counties with data, Charles Mix County is number 6 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 Charles Mix County: Butte County (48.5), Lincoln County (47.9), Haakon County (51.7).