How hard is the water in Codington County, SD?
21.4 grains per gallon
A softener will pay its way here.
The median hardness measured in Codington County, SD is 367 mg/L as calcium carbonate, which is 21.4 gpg. That is very hard on the USGS scale. It comes from 176 samples at 5 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 16.5 and 22.2 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: medium (how it is measured).
What to do next
At 21.4 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 14.3 to 22.4 gpg
The softest single sample on record in Codington County was 245 mg/L and the hardest 384 mg/L, a 2-fold gap. The top quarter of sites read above 22.2 gpg and the bottom quarter below 16.5 gpg.
Wells 19.5 gpg, rivers and lakes 21.4 gpg
2 groundwater samples from 2 wells put the median at 333.5 mg/L. 174 surface samples from 3 sites put it at 367 mg/L. In Codington County the rivers and lakes come out 1.9 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. 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 32,000-grain unit covers a week between regenerations. Expect about 468 lb of salt a year (12 bags of 40 lb, about $84), 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 $184 a year.
Sizing at 21.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,284 | 24,000 | 156 lb |
| 2 | 2,568 | 24,000 | 312 lb |
| 4 | 5,136 | 40,000 | 625 lb |
| 6 | 7,704 | 64,000 | 937 lb |
Codington County against the rest of South Dakota
Among the 55 South Dakota counties with data, Codington County is number 30 of 55 counting from the hardest. Across the whole country it is harder than 87% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Codington County: Brown County (21.2), Hand County (19.9), Yankton County (19.1).