How hard is the water in Bennett County, SD?
5.8 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Bennett County, SD is 100 mg/L as calcium carbonate, which is 5.8 gpg. That is moderately hard on the USGS scale. It comes from 7 samples at 7 sites between 1994 and 1995, drawn from groundwater wells, which is what most taps and private wells in the county draw on.
How much it varies here
Half the sites came in between 1.2 and 7.8 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: medium (how it is measured).
What to do next
At 5.8 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Bennett County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on when a softener is not worth it.
From 0.8 to 8.3 gpg
The softest single sample on record in Bennett County was 14.3 mg/L and the hardest 142 mg/L, a 10-fold gap. The top quarter of sites read above 7.8 gpg and the bottom quarter below 1.2 gpg.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 128 lb of salt a year (4 bags of 40 lb, about $23), 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 $123 a year.
Sizing at 5.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 348 | 24,000 | 42 lb |
| 2 | 696 | 24,000 | 85 lb |
| 4 | 1,392 | 24,000 | 169 lb |
| 6 | 2,088 | 24,000 | 254 lb |
Bennett County against the rest of South Dakota
Among the 55 South Dakota counties with data, Bennett County is number 51 of 55 counting from the hardest. Across the whole country it is harder than 34% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Bennett County: Oglala Lakota County (8.2), Todd County (8.3), Jackson County (2.7).