How hard is the water in Guthrie County, IA?
18.1 grains per gallon
A softener will pay its way here.
The median hardness measured in Guthrie County, IA is 310 mg/L as calcium carbonate, which is 18.1 gpg. That is very hard on the USGS scale. It comes from 7 samples at 5 sites between 1992 and 2013, 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 10.8 and 19.3 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 18.1 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 9.8 to 20.4 gpg
The softest single sample on record in Guthrie County was 168.5 mg/L and the hardest 350 mg/L, a 2-fold gap. The top quarter of sites read above 19.3 gpg and the bottom quarter below 10.8 gpg.
Wells 18.1 gpg, rivers and lakes 16.2 gpg
7 groundwater samples from 5 wells put the median at 310 mg/L. 1 surface samples from 1 sites put it at 277 mg/L. In Guthrie County the wells come out 1.9 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 396 lb of salt a year (10 bags of 40 lb, about $71), 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 $171 a year.
Sizing at 18.1 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,086 | 24,000 | 132 lb |
| 2 | 2,172 | 24,000 | 264 lb |
| 4 | 4,344 | 32,000 | 529 lb |
| 6 | 6,516 | 48,000 | 793 lb |
Guthrie County against the rest of Iowa
Among the 93 Iowa counties with data, Guthrie County is number 62 of 93 counting from the hardest. Across the whole country it is harder than 79% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Guthrie County: Winneshiek County (18.1), Jefferson County (18.4), Benton County (18.6).