How hard is the water in Union County, SD?
32.5 grains per gallon
A softener will pay its way here.
The median hardness measured in Union County, SD is 557 mg/L as calcium carbonate, which is 32.5 gpg. That is very hard on the USGS scale. It comes from 169 samples at 6 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 31.8 and 67.4 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 32.5 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 26.0 to 84.7 gpg
The softest single sample on record in Union County was 445.3 mg/L and the hardest 1,450 mg/L, a 3-fold gap. The top quarter of sites read above 67.4 gpg and the bottom quarter below 31.8 gpg.
What a softener would cost to run
For a household of 3, a 48,000-grain unit covers a week between regenerations. Expect about 710 lb of salt a year (18 bags of 40 lb, about $128), 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 $228 a year.
Sizing at 32.5 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,950 | 24,000 | 237 lb |
| 2 | 3,900 | 32,000 | 475 lb |
| 4 | 7,800 | 64,000 | 949 lb |
| 6 | 11,700 | twin tank | 1,424 lb |
Union County against the rest of South Dakota
Among the 55 South Dakota counties with data, Union County is number 16 of 55 counting from the hardest. Across the whole country it is harder than 96% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Union County: Davison County (31.6), Douglas County (33.9), Jones County (30.2).