How hard is the water in Cerro Gordo County, IA?
19.3 grains per gallon
A softener will pay its way here.
The median hardness measured in Cerro Gordo County, IA is 330 mg/L as calcium carbonate, which is 19.3 gpg. That is very hard on the USGS scale. It comes from 15 samples at 7 sites between 1991 and 2017, 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 18.4 and 20.5 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 19.3 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 17.3 to 22.2 gpg
The softest single sample on record in Cerro Gordo County was 297 mg/L and the hardest 380 mg/L, a 1-fold gap. The top quarter of sites read above 20.5 gpg and the bottom quarter below 18.4 gpg.
Wells 19.3 gpg, rivers and lakes 17.9 gpg
15 groundwater samples from 7 wells put the median at 330 mg/L. 2 surface samples from 2 sites put it at 306.5 mg/L. In Cerro Gordo County the wells come out 1.4 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 32,000-grain unit covers a week between regenerations. Expect about 421 lb of salt a year (11 bags of 40 lb, about $76), 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 $176 a year.
Sizing at 19.3 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,158 | 24,000 | 141 lb |
| 2 | 2,316 | 24,000 | 282 lb |
| 4 | 4,632 | 40,000 | 564 lb |
| 6 | 6,948 | 64,000 | 845 lb |
Cerro Gordo County against the rest of Iowa
Among the 93 Iowa counties with data, Cerro Gordo County is number 52 of 93 counting from the hardest. Across the whole country it is harder than 82% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Cerro Gordo County: Fayette County (19.3), Scott County (19.3), Johnson County (19.3).