How hard is the water in McMinn County, TN?
9.3 grains per gallon
A softener is worth it here.
The median hardness measured in McMinn County, TN is 160 mg/L as calcium carbonate, which is 9.3 gpg. That is hard on the USGS scale. It comes from 376 samples at 38 sites between 1997 and 2022, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 6.2 and 10.5 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: high (how it is measured).
What to do next
At 9.3 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 McMinn 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 0.4 to 11.7 gpg
The softest single sample on record in McMinn County was 7.7 mg/L and the hardest 200 mg/L, a 26-fold gap. The top quarter of sites read above 10.5 gpg and the bottom quarter below 6.2 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 9.3 gpg, rivers and lakes 9.3 gpg
4 groundwater samples from 3 wells put the median at 160 mg/L. 372 surface samples from 35 sites put it at 160 mg/L. In McMinn County the rivers and lakes come out 0.0 gpg harder. Here the surface water reads harder than the wells, which often points to streams fed by limestone springs or irrigation return flow. 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 204 lb of salt a year (6 bags of 40 lb, about $37), 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 $137 a year.
Sizing at 9.3 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 558 | 24,000 | 68 lb |
| 2 | 1,116 | 24,000 | 136 lb |
| 4 | 2,232 | 24,000 | 272 lb |
| 6 | 3,348 | 24,000 | 407 lb |
McMinn County against the rest of Tennessee
Among the 95 Tennessee counties with data, McMinn County is number 24 of 95 counting from the hardest. Across the whole country it is harder than 48% of counties.
Softest in Tennessee: Fayette County at 0.5 gpg. Hardest: Fentress County at 42.9 gpg. Closest to McMinn County: Sumner County (9.2), Anderson County (9.5), Houston County (9.1).