How hard is the water in Grundy County, IA?
20.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Grundy County, IA is 358 mg/L as calcium carbonate, which is 20.9 gpg. That is very hard on the USGS scale. It comes from 42 samples at 13 sites between 1990 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 16.5 and 25.7 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: high (how it is measured).
What to do next
At 20.9 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 10.3 to 46.4 gpg
The softest single sample on record in Grundy County was 176 mg/L and the hardest 795 mg/L, a 5-fold gap. The top quarter of sites read above 25.7 gpg and the bottom quarter below 16.5 gpg.
Wells 20.9 gpg, rivers and lakes 18.5 gpg
42 groundwater samples from 13 wells put the median at 358 mg/L. 1 surface samples from 1 sites put it at 317 mg/L. In Grundy County the wells come out 2.4 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 457 lb of salt a year (12 bags of 40 lb, about $82), 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 $182 a year.
Sizing at 20.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,254 | 24,000 | 153 lb |
| 2 | 2,508 | 24,000 | 305 lb |
| 4 | 5,016 | 40,000 | 610 lb |
| 6 | 7,524 | 64,000 | 915 lb |
Grundy County against the rest of Iowa
Among the 93 Iowa counties with data, Grundy County is number 39 of 93 counting from the hardest. Across the whole country it is harder than 86% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Grundy County: Osceola County (20.9), Hardin County (20.8), Hancock County (21).