How hard is the water in Dunn County, ND?
11.7 grains per gallon
A softener will pay its way here.
The median hardness measured in Dunn County, ND is 200 mg/L as calcium carbonate, which is 11.7 gpg. That is very hard on the USGS scale. It comes from 47 samples at 34 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 2 and 20.5 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: high (how it is measured).
What to do next
At 11.7 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. Because Dunn County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on sizing a softener for your household.
From 0.3 to 60.8 gpg
The softest single sample on record in Dunn County was 5.8 mg/L and the hardest 1,040 mg/L, a 179-fold gap. The top quarter of sites read above 20.5 gpg and the bottom quarter below 2 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 11.7 gpg, rivers and lakes 11.9 gpg
47 groundwater samples from 34 wells put the median at 200.3 mg/L. 230 surface samples from 16 sites put it at 204 mg/L. In Dunn County the rivers and lakes come out 0.2 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 24,000-grain unit covers a week between regenerations. Expect about 256 lb of salt a year (7 bags of 40 lb, about $46), 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 $146 a year.
Sizing at 11.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 702 | 24,000 | 85 lb |
| 2 | 1,404 | 24,000 | 171 lb |
| 4 | 2,808 | 24,000 | 342 lb |
| 6 | 4,212 | 32,000 | 512 lb |
Dunn County against the rest of North Dakota
Among the 53 North Dakota counties with data, Dunn County is number 48 of 53 counting from the hardest. Across the whole country it is harder than 57% of counties.
Softest in North Dakota: Hettinger County at 1.1 gpg. Hardest: Walsh County at 54 gpg. Closest to Dunn County: Bowman County (11.7), Billings County (11.8), Pierce County (12.8).