How hard is the water in LaSalle County, IL?
22.7 grains per gallon
A softener will pay its way here.
The median hardness measured in LaSalle County, IL is 389 mg/L as calcium carbonate, which is 22.7 gpg. That is very hard on the USGS scale. It comes from 15 samples at 8 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 18.8 and 30.8 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 22.7 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 8.6 to 42.4 gpg
The softest single sample on record in LaSalle County was 147 mg/L and the hardest 725 mg/L, a 5-fold gap. The top quarter of sites read above 30.8 gpg and the bottom quarter below 18.8 gpg.
Wells 22.7 gpg, rivers and lakes 18.8 gpg
15 groundwater samples from 8 wells put the median at 388.5 mg/L. 624 surface samples from 28 sites put it at 322.5 mg/L. In LaSalle 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 32,000-grain unit covers a week between regenerations. Expect about 496 lb of salt a year (13 bags of 40 lb, about $89), 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 $189 a year.
Sizing at 22.7 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,362 | 24,000 | 166 lb |
| 2 | 2,724 | 24,000 | 331 lb |
| 4 | 5,448 | 40,000 | 663 lb |
| 6 | 8,172 | 64,000 | 994 lb |
LaSalle County against the rest of Illinois
Among the 102 Illinois counties with data, LaSalle County is number 10 of 102 counting from the hardest. Across the whole country it is harder than 89% of counties.
Softest in Illinois: Pope County at 4.3 gpg. Hardest: Cook County at 34.8 gpg. Closest to LaSalle County: Gallatin County (22.5), Ogle County (22.3), Cass County (22.2).