How hard is the water in De Witt County, IL?
18.5 grains per gallon
A softener will pay its way here.
The median hardness measured in De Witt County, IL is 318 mg/L as calcium carbonate, which is 18.5 gpg. That is very hard on the USGS scale. It comes from 71 samples at 24 sites between 1990 and 2018, 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 16.2 and 21.1 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 18.5 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 15.5 to 26.5 gpg
The softest single sample on record in De Witt County was 266 mg/L and the hardest 454 mg/L, a 2-fold gap. The top quarter of sites read above 21.1 gpg and the bottom quarter below 16.2 gpg.
Wells 18.5 gpg, rivers and lakes 17.2 gpg
71 groundwater samples from 24 wells put the median at 317.5 mg/L. 190 surface samples from 4 sites put it at 295 mg/L. In De Witt County the wells come out 1.3 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 405 lb of salt a year (11 bags of 40 lb, about $73), 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 $173 a year.
Sizing at 18.5 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,110 | 24,000 | 135 lb |
| 2 | 2,220 | 24,000 | 270 lb |
| 4 | 4,440 | 32,000 | 540 lb |
| 6 | 6,660 | 48,000 | 810 lb |
De Witt County against the rest of Illinois
Among the 102 Illinois counties with data, De Witt County is number 42 of 102 counting from the hardest. Across the whole country it is harder than 80% of counties.
Softest in Illinois: Pope County at 4.3 gpg. Hardest: Cook County at 34.8 gpg. Closest to De Witt County: Champaign County (18.4), Henderson County (18.4), Vermilion County (18.7).