How hard is the water in Clark County, IL?
16.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Clark County, IL is 290 mg/L as calcium carbonate, which is 16.9 gpg. That is very hard on the USGS scale. It comes from 18 samples at 5 sites between 1990 and 2001, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 15.4 and 17.4 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: medium (how it is measured).
What to do next
At 16.9 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 10.6 to 21.6 gpg
The softest single sample on record in Clark County was 181 mg/L and the hardest 370 mg/L, a 2-fold gap. The top quarter of sites read above 17.4 gpg and the bottom quarter below 15.4 gpg.
Wells 19.3 gpg, rivers and lakes 15.4 gpg
9 groundwater samples from 2 wells put the median at 330 mg/L. 9 surface samples from 3 sites put it at 263 mg/L. In Clark County the wells come out 3.9 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river 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 370 lb of salt a year (10 bags of 40 lb, about $67), 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 $167 a year.
Sizing at 16.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,014 | 24,000 | 123 lb |
| 2 | 2,028 | 24,000 | 247 lb |
| 4 | 4,056 | 32,000 | 493 lb |
| 6 | 6,084 | 48,000 | 740 lb |
Clark County against the rest of Illinois
Among the 102 Illinois counties with data, Clark County is number 54 of 102 counting from the hardest. Across the whole country it is harder than 76% of counties.
Softest in Illinois: Pope County at 4.3 gpg. Hardest: Cook County at 34.8 gpg. Closest to Clark County: Cumberland County (17.2), Mercer County (17.3), Rock Island County (17.3).