How hard is the water in Jefferson County, IA?
18.4 grains per gallon
A softener will pay its way here.
The median hardness measured in Jefferson County, IA is 315 mg/L as calcium carbonate, which is 18.4 gpg. That is very hard on the USGS scale. It comes from 12 samples at 3 sites between 1997 and 2017, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 11.6 and 19.6 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 18.4 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 4.9 to 20.7 gpg
The softest single sample on record in Jefferson County was 83.2 mg/L and the hardest 355 mg/L, a 4-fold gap. The top quarter of sites read above 19.6 gpg and the bottom quarter below 11.6 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 402 lb of salt a year (11 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 18.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 1,104 | 24,000 | 134 lb |
| 2 | 2,208 | 24,000 | 269 lb |
| 4 | 4,416 | 32,000 | 537 lb |
| 6 | 6,624 | 48,000 | 806 lb |
Jefferson County against the rest of Iowa
Among the 93 Iowa counties with data, Jefferson County is number 60 of 93 counting from the hardest. Across the whole country it is harder than 80% of counties.
Softest in Iowa: Taylor County at 8.2 gpg. Hardest: Pocahontas County at 45.3 gpg. Closest to Jefferson County: Benton County (18.6), Guthrie County (18.1), Winneshiek County (18.1).