How hard is the water in Douglas County, IL?
12.6 grains per gallon
A softener will pay its way here.
The median hardness measured in Douglas County, IL is 215 mg/L as calcium carbonate, which is 12.6 gpg. That is very hard on the USGS scale. It comes from 6 samples at 6 sites between 1990 and 2003, 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 10.4 and 15.2 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: medium (how it is measured).
What to do next
At 12.6 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 Douglas 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 9.9 to 18.1 gpg
The softest single sample on record in Douglas County was 170 mg/L and the hardest 310 mg/L, a 2-fold gap. The top quarter of sites read above 15.2 gpg and the bottom quarter below 10.4 gpg.
Wells 12.6 gpg, rivers and lakes 17.2 gpg
6 groundwater samples from 6 wells put the median at 215 mg/L. 188 surface samples from 8 sites put it at 294.5 mg/L. In Douglas County the rivers and lakes come out 4.6 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 274 lb of salt a year (7 bags of 40 lb, about $49), 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 $149 a year.
Sizing at 12.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 756 | 24,000 | 92 lb |
| 2 | 1,512 | 24,000 | 184 lb |
| 4 | 3,024 | 24,000 | 368 lb |
| 6 | 4,536 | 32,000 | 552 lb |
Douglas County against the rest of Illinois
Among the 102 Illinois counties with data, Douglas County is number 80 of 102 counting from the hardest. Across the whole country it is harder than 60% of counties.
Softest in Illinois: Pope County at 4.3 gpg. Hardest: Cook County at 34.8 gpg. Closest to Douglas County: Massac County (12.3), Union County (12.3), Hardin County (13.1).