How hard is the water in Mitchell County, IA?
16.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Mitchell County, IA is 285 mg/L as calcium carbonate, which is 16.6 gpg. That is very hard on the USGS scale. It comes from 48 samples at 6 sites between 1990 and 2020, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 16.3 and 17.4 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 16.6 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 15.6 to 21.1 gpg
The softest single sample on record in Mitchell County was 267 mg/L and the hardest 362 mg/L, a 1-fold gap. The top quarter of sites read above 17.4 gpg and the bottom quarter below 16.3 gpg.
Wells 17.2 gpg, rivers and lakes 15.9 gpg
32 groundwater samples from 4 wells put the median at 295 mg/L. 16 surface samples from 2 sites put it at 272.5 mg/L. In Mitchell County the wells come out 1.3 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. 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 364 lb of salt a year (10 bags of 40 lb, about $65), 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 $165 a year.
Sizing at 16.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 996 | 24,000 | 121 lb |
| 2 | 1,992 | 24,000 | 242 lb |
| 4 | 3,984 | 32,000 | 485 lb |
| 6 | 5,976 | 48,000 | 727 lb |
Mitchell County against the rest of Iowa
Among the 93 Iowa counties with data, Mitchell County is number 69 of 93 counting from the hardest. Across the whole country it is harder than 75% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Mitchell County: Lucas County (16.6), Bremer County (16.5), Floyd County (16.9).