How hard is the water in McDonald County, MO?
9.1 grains per gallon
A softener is worth it here.
The median hardness measured in McDonald County, MO is 156 mg/L as calcium carbonate, which is 9.1 gpg. That is hard on the USGS scale. It comes from 7 samples at 6 sites between 1990 and 2026, 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 7.2 and 10.8 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 9.1 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 McDonald 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 3.9 to 14.0 gpg
The softest single sample on record in McDonald County was 67.4 mg/L and the hardest 239 mg/L, a 4-fold gap. The top quarter of sites read above 10.8 gpg and the bottom quarter below 7.2 gpg.
Wells 9.1 gpg, rivers and lakes 8.5 gpg
7 groundwater samples from 6 wells put the median at 155.5 mg/L. 609 surface samples from 28 sites put it at 145.8 mg/L. In McDonald County the wells come out 0.6 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.
What a softener would cost to run
For a household of 3, a 24,000-grain unit covers a week between regenerations. Expect about 198 lb of salt a year (5 bags of 40 lb, about $36), 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 $136 a year.
Sizing at 9.1 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 546 | 24,000 | 66 lb |
| 2 | 1,092 | 24,000 | 133 lb |
| 4 | 2,184 | 24,000 | 266 lb |
| 6 | 3,276 | 24,000 | 399 lb |
McDonald County against the rest of Missouri
Among the 110 Missouri counties with data, McDonald County is number 98 of 110 counting from the hardest. Across the whole country it is harder than 47% of counties.
Softest in Missouri: Livingston County at 4.1 gpg. Hardest: Reynolds County at 96.7 gpg. Closest to McDonald County: Stoddard County (9), Mississippi County (9.2), Ralls County (8.8).