How hard is the water in Sioux County, ND?
3.6 grains per gallon
Optional: a softener helps, but plenty of homes skip it.
The median hardness measured in Sioux County, ND is 62 mg/L as calcium carbonate, which is 3.6 gpg. That is moderately hard on the USGS scale. It comes from 41 samples at 33 sites between 1991 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 and 6.5 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 3.6 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Sioux County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on when a softener is not worth it.
From 0.5 to 32.8 gpg
The softest single sample on record in Sioux County was 9.3 mg/L and the hardest 562 mg/L, a 60-fold gap. The top quarter of sites read above 6.5 gpg and the bottom quarter below 1 gpg.
Wells 3.6 gpg, rivers and lakes 12.1 gpg
41 groundwater samples from 33 wells put the median at 62.1 mg/L. 124 surface samples from 8 sites put it at 207.3 mg/L. In Sioux County the rivers and lakes come out 8.5 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 79 lb of salt a year (2 bags of 40 lb, about $14), 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 $114 a year.
Sizing at 3.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 216 | 24,000 | 26 lb |
| 2 | 432 | 24,000 | 53 lb |
| 4 | 864 | 24,000 | 105 lb |
| 6 | 1,296 | 24,000 | 158 lb |
Sioux County against the rest of North Dakota
Among the 53 North Dakota counties with data, Sioux County is number 49 of 53 counting from the hardest. Across the whole country it is harder than 25% of counties.
Softest in North Dakota: Hettinger County at 1.1 gpg. Hardest: Walsh County at 54 gpg. Closest to Sioux County: Adams County (3.4), McHenry County (2.8), Morton County (1.9).