How hard is the water in Brown County, SD?
21.2 grains per gallon
A softener will pay its way here.
The median hardness measured in Brown County, SD is 362 mg/L as calcium carbonate, which is 21.2 gpg. That is very hard on the USGS scale. It comes from 460 samples at 12 sites between 1990 and 2014, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 19.8 and 28.8 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 21.2 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 9.3 to 37.0 gpg
The softest single sample on record in Brown County was 160 mg/L and the hardest 634 mg/L, a 4-fold gap. The top quarter of sites read above 28.8 gpg and the bottom quarter below 19.8 gpg.
Wells 9.3 gpg, rivers and lakes 21.6 gpg
1 groundwater samples from 1 wells put the median at 160 mg/L. 459 surface samples from 11 sites put it at 369 mg/L. In Brown County the rivers and lakes come out 12.3 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 32,000-grain unit covers a week between regenerations. Expect about 462 lb of salt a year (12 bags of 40 lb, about $83), 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 $183 a year.
Sizing at 21.2 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,272 | 24,000 | 155 lb |
| 2 | 2,544 | 24,000 | 310 lb |
| 4 | 5,088 | 40,000 | 619 lb |
| 6 | 7,632 | 64,000 | 929 lb |
Brown County against the rest of South Dakota
Among the 55 South Dakota counties with data, Brown County is number 31 of 55 counting from the hardest. Across the whole country it is harder than 86% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Brown County: Codington County (21.4), Hand County (19.9), Yankton County (19.1).