How hard is the water in Kankakee County, IL?
11.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Kankakee County, IL is 205 mg/L as calcium carbonate, which is 11.9 gpg. That is very hard on the USGS scale. It comes from 38 samples at 10 sites between 1990 and 2021, 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 7.2 and 15.1 gpg. That spread crosses a decision line, so some homes here land on a different answer. A $10 test strip on your own tap settles it. Confidence in the county figure: high (how it is measured).
What to do next
At 11.9 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. Because Kankakee County straddles a decision line, check your own tap with a $10 test strip before you spend anything.
More on sizing a softener for your household.
From 0.8 to 21.6 gpg
The softest single sample on record in Kankakee County was 13 mg/L and the hardest 370 mg/L, a 28-fold gap. The top quarter of sites read above 15.1 gpg and the bottom quarter below 7.2 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 11.9 gpg, rivers and lakes 20.1 gpg
38 groundwater samples from 10 wells put the median at 204.5 mg/L. 266 surface samples from 15 sites put it at 344 mg/L. In Kankakee County the rivers and lakes come out 8.2 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. A utility here that draws from the aquifer can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 261 lb of salt a year (7 bags of 40 lb, about $47), 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 $147 a year.
Sizing at 11.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 714 | 24,000 | 87 lb |
| 2 | 1,428 | 24,000 | 174 lb |
| 4 | 2,856 | 24,000 | 347 lb |
| 6 | 4,284 | 32,000 | 521 lb |
Kankakee County against the rest of Illinois
Among the 102 Illinois counties with data, Kankakee County is number 83 of 102 counting from the hardest. Across the whole country it is harder than 58% of counties.
Softest in Illinois: Pope County at 4.3 gpg. Hardest: Cook County at 34.8 gpg. Closest to Kankakee County: Alexander County (12), White County (11.9), Washington County (11.7).