How hard is the water in Mountrail County, ND?
15.5 grains per gallon
A softener will pay its way here.
The median hardness measured in Mountrail County, ND is 265 mg/L as calcium carbonate, which is 15.5 gpg. That is very hard on the USGS scale. It comes from 91 samples at 64 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 1.7 and 38.7 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 15.5 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 Mountrail 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 121.5 gpg
The softest single sample on record in Mountrail County was 5.1 mg/L and the hardest 2,080 mg/L, a 408-fold gap. The top quarter of sites read above 38.7 gpg and the bottom quarter below 1.7 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 15.5 gpg, rivers and lakes 20.2 gpg
91 groundwater samples from 64 wells put the median at 265 mg/L. 385 surface samples from 16 sites put it at 346.3 mg/L. In Mountrail County the rivers and lakes come out 4.7 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. A utility here that draws from the aquifer 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 338 lb of salt a year (9 bags of 40 lb, about $61), 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 $161 a year.
Sizing at 15.5 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 930 | 24,000 | 113 lb |
| 2 | 1,860 | 24,000 | 226 lb |
| 4 | 3,720 | 32,000 | 453 lb |
| 6 | 5,580 | 40,000 | 679 lb |
Mountrail County against the rest of North Dakota
Among the 53 North Dakota counties with data, Mountrail County is number 39 of 53 counting from the hardest. Across the whole country it is harder than 71% of counties.
Softest in North Dakota: Hettinger County at 1.1 gpg. Hardest: Walsh County at 54 gpg. Closest to Mountrail County: Eddy County (15.7), Emmons County (15), Renville County (16).