How hard is the water in Davison County, SD?
31.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Davison County, SD is 541 mg/L as calcium carbonate, which is 31.6 gpg. That is very hard on the USGS scale. It comes from 79 samples at 3 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 29.6 and 54.3 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 31.6 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 27.6 to 77.1 gpg
The softest single sample on record in Davison County was 472 mg/L and the hardest 1,320 mg/L, a 3-fold gap. The top quarter of sites read above 54.3 gpg and the bottom quarter below 29.6 gpg.
Wells 77.1 gpg, rivers and lakes 29.6 gpg
1 groundwater samples from 1 wells put the median at 1320 mg/L. 78 surface samples from 2 sites put it at 506.3 mg/L. In Davison County the wells come out 47.5 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 40,000-grain unit covers a week between regenerations. Expect about 690 lb of salt a year (18 bags of 40 lb, about $124), 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 $224 a year.
Sizing at 31.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,896 | 24,000 | 231 lb |
| 2 | 3,792 | 32,000 | 461 lb |
| 4 | 7,584 | 64,000 | 923 lb |
| 6 | 11,376 | 80,000 | 1,384 lb |
Davison County against the rest of South Dakota
Among the 55 South Dakota counties with data, Davison County is number 17 of 55 counting from the hardest. Across the whole country it is harder than 95% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Davison County: Union County (32.5), Jones County (30.2), Douglas County (33.9).