How hard is the water in Overton County, TN?
8.6 grains per gallon
A softener is worth it here.
The median hardness measured in Overton County, TN is 148 mg/L as calcium carbonate, which is 8.6 gpg. That is hard on the USGS scale. It comes from 338 samples at 22 sites between 1990 and 2016, drawn from every sampling site in the county, wells and surface water together.
How much it varies here
Half the sites came in between 7.9 and 9.9 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: high (how it is measured).
What to do next
At 8.6 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.
More on sizing a softener for your household.
From 1.0 to 14.4 gpg
The softest single sample on record in Overton County was 17 mg/L and the hardest 247 mg/L, a 15-fold gap. The top quarter of sites read above 9.9 gpg and the bottom quarter below 7.9 gpg. So even here some sites draw water soft enough to need nothing at all.
Wells 10.6 gpg, rivers and lakes 8.6 gpg
2 groundwater samples from 1 wells put the median at 182 mg/L. 336 surface samples from 21 sites put it at 147 mg/L. In Overton County the wells come out 2.0 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 188 lb of salt a year (5 bags of 40 lb, about $34), 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 $134 a year.
Sizing at 8.6 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 516 | 24,000 | 63 lb |
| 2 | 1,032 | 24,000 | 126 lb |
| 4 | 2,064 | 24,000 | 251 lb |
| 6 | 3,096 | 24,000 | 377 lb |
Overton County against the rest of Tennessee
Among the 95 Tennessee counties with data, Overton County is number 35 of 95 counting from the hardest. Across the whole country it is harder than 45% of counties.
Softest in Tennessee: Fayette County at 0.5 gpg. Hardest: Fentress County at 42.9 gpg. Closest to Overton County: Montgomery County (8.6), Blount County (8.7), Cannon County (8.7).