How hard is the water in Knox County, MO?
10.4 grains per gallon
A softener is worth it here.
The median hardness measured in Knox County, MO is 178 mg/L as calcium carbonate, which is 10.4 gpg. That is hard on the USGS scale. It comes from 27 samples at 3 sites between 2010 and 2024, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 8.6 and 10.7 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 10.4 gpg a softener is worth getting, mainly to protect the water heater and cut soap use. Get at least two quotes, ask each installer what grain capacity they are fitting, and check it against the sizing table below. Because Knox 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 6.7 to 11.0 gpg
The softest single sample on record in Knox County was 115 mg/L and the hardest 189 mg/L, a 2-fold gap. The top quarter of sites read above 10.7 gpg and the bottom quarter below 8.6 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 227 lb of salt a year (6 bags of 40 lb, about $41), 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 $141 a year.
Sizing at 10.4 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 624 | 24,000 | 76 lb |
| 2 | 1,248 | 24,000 | 152 lb |
| 4 | 2,496 | 24,000 | 304 lb |
| 6 | 3,744 | 32,000 | 456 lb |
Knox County against the rest of Missouri
Among the 110 Missouri counties with data, Knox County is number 83 of 110 counting from the hardest. Across the whole country it is harder than 52% of counties.
Softest in Missouri: Livingston County at 4.1 gpg. Hardest: Reynolds County at 96.7 gpg. Closest to Knox County: Barton County (10.4), Sullivan County (10.4), Dunklin County (10.5).