How hard is the water in Moody County, SD?
28 grains per gallon
A softener will pay its way here.
The median hardness measured in Moody County, SD is 480 mg/L as calcium carbonate, which is 28 gpg. That is very hard on the USGS scale. It comes from 473 samples at 11 sites between 1999 and 2021, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 26 and 29.7 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: high (how it is measured).
What to do next
At 28 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 19.9 to 31.0 gpg
The softest single sample on record in Moody County was 340 mg/L and the hardest 530 mg/L, a 2-fold gap. The top quarter of sites read above 29.7 gpg and the bottom quarter below 26 gpg.
Wells 27.5 gpg, rivers and lakes 28.3 gpg
67 groundwater samples from 3 wells put the median at 470 mg/L. 406 surface samples from 8 sites put it at 484.8 mg/L. In Moody County the rivers and lakes come out 0.8 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 40,000-grain unit covers a week between regenerations. Expect about 612 lb of salt a year (16 bags of 40 lb, about $110), 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 $210 a year.
Sizing at 28 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,680 | 24,000 | 204 lb |
| 2 | 3,360 | 24,000 | 409 lb |
| 4 | 6,720 | 48,000 | 818 lb |
| 6 | 10,080 | 80,000 | 1,226 lb |
Moody County against the rest of South Dakota
Among the 55 South Dakota counties with data, Moody County is number 20 of 55 counting from the hardest. Across the whole country it is harder than 94% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Moody County: Brookings County (27.9), Campbell County (27.8), Deuel County (28.6).