How hard is the water in Boone County, IL?
20.7 grains per gallon
A softener will pay its way here.
The median hardness measured in Boone County, IL is 355 mg/L as calcium carbonate, which is 20.7 gpg. That is very hard on the USGS scale. It comes from 33 samples at 21 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 18.6 and 22 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 20.7 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 16.5 to 24.7 gpg
The softest single sample on record in Boone County was 282 mg/L and the hardest 422 mg/L, a 1-fold gap. The top quarter of sites read above 22 gpg and the bottom quarter below 18.6 gpg.
Wells 20.7 gpg, rivers and lakes 21.5 gpg
33 groundwater samples from 21 wells put the median at 355 mg/L. 91 surface samples from 6 sites put it at 367.5 mg/L. In Boone County the rivers and lakes come out 0.8 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. 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 453 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 20.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,242 | 24,000 | 151 lb |
| 2 | 2,484 | 24,000 | 302 lb |
| 4 | 4,968 | 40,000 | 604 lb |
| 6 | 7,452 | 64,000 | 907 lb |
Boone County against the rest of Illinois
Among the 102 Illinois counties with data, Boone County is number 23 of 102 counting from the hardest. Across the whole country it is harder than 85% of counties.
Softest in Illinois: Pope County at 4.3 gpg. Hardest: Cook County at 34.8 gpg. Closest to Boone County: Jo Daviess County (20.7), McDonough County (20.6), Fulton County (20.6).