How hard is the water in McCook County, SD?
46.6 grains per gallon
A softener will pay its way here.
The median hardness measured in McCook County, SD is 798 mg/L as calcium carbonate, which is 46.6 gpg. That is very hard on the USGS scale. It comes from 67 samples at 3 sites between 1993 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 35.3 and 48.7 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: medium (how it is measured).
What to do next
At 46.6 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 24.0 to 50.8 gpg
The softest single sample on record in McCook County was 410 mg/L and the hardest 870 mg/L, a 2-fold gap. The top quarter of sites read above 48.7 gpg and the bottom quarter below 35.3 gpg.
What a softener would cost to run
For a household of 3, a 64,000-grain unit covers a week between regenerations. Expect about 1,018 lb of salt a year (26 bags of 40 lb, about $183), 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 $283 a year.
Sizing at 46.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 2,796 | 24,000 | 340 lb |
| 2 | 5,592 | 40,000 | 680 lb |
| 4 | 11,184 | 80,000 | 1,361 lb |
| 6 | 16,776 | twin tank | 2,041 lb |
McCook County against the rest of South Dakota
Among the 55 South Dakota counties with data, McCook County is number 9 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 McCook County: Clay County (46.5), Lincoln County (47.9), Butte County (48.5).