How hard is the water in Perkins County, SD?

15.1 grains per gallon

A softener will pay its way here.

The median hardness measured in Perkins County, SD is 258 mg/L as calcium carbonate, which is 15.1 gpg. That is very hard on the USGS scale. It comes from 192 samples at 8 sites between 1990 and 2010, drawn from every sampling site in the county, wells and surface water together.

How much it varies here

Half the sites came in between 12.9 and 25.5 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 15.1 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 7.5 to 42.1 gpg

The softest single sample on record in Perkins County was 129 mg/L and the hardest 720 mg/L, a 6-fold gap. The top quarter of sites read above 25.5 gpg and the bottom quarter below 12.9 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 329 lb of salt a year (9 bags of 40 lb, about $59), 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 $159 a year.

Sizing at 15.1 gpg

Perkins County against the rest of South Dakota

Among the 55 South Dakota counties with data, Perkins County is number 40 of 55 counting from the hardest. Across the whole country it is harder than 69% of counties.

Softest in South Dakota: Dewey County at 0.5 gpg. Hardest: Hanson County at 84.7 gpg. Closest to Perkins County: Custer County (15.5), Bon Homme County (14), Stanley County (16.1).