How hard is the water in Douglas County, SD?
33.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Douglas County, SD is 580 mg/L as calcium carbonate, which is 33.9 gpg. That is very hard on the USGS scale. It comes from 6 samples at 2 sites between 2001 and 2002, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 33.9 and 33.9 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: low (how it is measured).
What to do next
At 33.9 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 33.9 to 33.9 gpg
The softest single sample on record in Douglas County was 580 mg/L and the hardest 580 mg/L, a 1-fold gap. The top quarter of sites read above 33.9 gpg and the bottom quarter below 33.9 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 740 lb of salt a year (19 bags of 40 lb, about $133), 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 $233 a year.
Sizing at 33.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 2,034 | 24,000 | 247 lb |
| 2 | 4,068 | 32,000 | 495 lb |
| 4 | 8,136 | 64,000 | 990 lb |
| 6 | 12,204 | twin tank | 1,485 lb |
Douglas County against the rest of South Dakota
Among the 55 South Dakota counties with data, Douglas County is number 15 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 Douglas County: Union County (32.5), Buffalo County (35.3), Davison County (31.6).