How hard is the water in Marion County, MO?
9.8 grains per gallon
A softener is worth it here.
The median hardness measured in Marion County, MO is 169 mg/L as calcium carbonate, which is 9.8 gpg. That is hard on the USGS scale. It comes from 164 samples at 7 sites between 1992 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 6.9 and 12.4 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 9.8 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 Marion 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 5.5 to 13.9 gpg
The softest single sample on record in Marion County was 93.9 mg/L and the hardest 237.5 mg/L, a 3-fold gap. The top quarter of sites read above 12.4 gpg and the bottom quarter below 6.9 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 215 lb of salt a year (6 bags of 40 lb, about $39), 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 $139 a year.
Sizing at 9.8 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 588 | 24,000 | 72 lb |
| 2 | 1,176 | 24,000 | 143 lb |
| 4 | 2,352 | 24,000 | 286 lb |
| 6 | 3,528 | 32,000 | 429 lb |
Marion County against the rest of Missouri
Among the 110 Missouri counties with data, Marion County is number 91 of 110 counting from the hardest. Across the whole country it is harder than 50% of counties.
Softest in Missouri: Livingston County at 4.1 gpg. Hardest: Reynolds County at 96.7 gpg. Closest to Marion County: Ripley County (9.9), Christian County (9.9), Wright County (10).