How hard is the water in Lawrence County, SD?
17.2 grains per gallon
A softener will pay its way here.
The median hardness measured in Lawrence County, SD is 294 mg/L as calcium carbonate, which is 17.2 gpg. That is very hard on the USGS scale. It comes from 51 samples at 48 sites between 1990 and 2023, 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 11.7 and 21.2 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 17.2 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 0.4 to 105.1 gpg
The softest single sample on record in Lawrence County was 7 mg/L and the hardest 1,800 mg/L, a 257-fold gap. The top quarter of sites read above 21.2 gpg and the bottom quarter below 11.7 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 17.2 gpg, rivers and lakes 13.7 gpg
51 groundwater samples from 48 wells put the median at 294 mg/L. 1,485 surface samples from 56 sites put it at 235.3 mg/L. In Lawrence County the wells come out 3.5 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 24,000-grain unit covers a week between regenerations. Expect about 375 lb of salt a year (10 bags of 40 lb, about $68), 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 $168 a year.
Sizing at 17.2 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,032 | 24,000 | 126 lb |
| 2 | 2,064 | 24,000 | 251 lb |
| 4 | 4,128 | 32,000 | 502 lb |
| 6 | 6,192 | 48,000 | 753 lb |
Lawrence County against the rest of South Dakota
Among the 55 South Dakota counties with data, Lawrence County is number 35 of 55 counting from the hardest. Across the whole country it is harder than 76% of counties.
Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Lawrence County: Mellette County (17), Faulk County (17.8), Hughes County (16.4).