How hard is the water in Johnson County, IN?

18.2 grains per gallon

A softener will pay its way here.

The median hardness measured in Johnson County, IN is 312 mg/L as calcium carbonate, which is 18.2 gpg. That is very hard on the USGS scale. It comes from 358 samples at 13 sites between 1991 and 2004, drawn from every sampling site in the county, wells and surface water together.

How much it varies here

Half the sites came in between 17.7 and 19 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 18.2 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 13.3 to 19.9 gpg

The softest single sample on record in Johnson County was 228 mg/L and the hardest 340 mg/L, a 1-fold gap. The top quarter of sites read above 19 gpg and the bottom quarter below 17.7 gpg.

What a softener would cost to run

For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 398 lb of salt a year (10 bags of 40 lb, about $72), 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 $172 a year.

Sizing at 18.2 gpg

Johnson County against the rest of Indiana

Among the 91 Indiana counties with data, Johnson County is number 33 of 91 counting from the hardest. Across the whole country it is harder than 79% of counties.

Softest in Indiana: Brown County at 3.8 gpg. Hardest: Warrick County at 40.3 gpg. Closest to Johnson County: Montgomery County (18.3), Tipton County (18.3), Howard County (18.1).