How hard is the water in Smith County, TN?

5 grains per gallon

Optional: a softener helps, but plenty of homes skip it.

The median hardness measured in Smith County, TN is 85 mg/L as calcium carbonate, which is 5 gpg. That is moderately hard on the USGS scale. It comes from 499 samples at 18 sites between 1990 and 2020, drawn from every sampling site in the county, wells and surface water together.

How much it varies here

Half the sites came in between 4.8 and 7.9 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 5 gpg this is your call. Look for white film on glasses and crust on the shower head: if you see little of either, you can live without one. If you do want one, a 24,000-grain unit is enough, so ask for that size rather than a bigger one. Because Smith County straddles a decision line, check your own tap with a $10 test strip before you spend anything.

More on when a softener is not worth it.

From 4.3 to 13.7 gpg

The softest single sample on record in Smith County was 73.8 mg/L and the hardest 234.5 mg/L, a 3-fold gap. The top quarter of sites read above 7.9 gpg and the bottom quarter below 4.8 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 109 lb of salt a year (3 bags of 40 lb, about $20), 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 $120 a year.

Sizing at 5 gpg

Smith County against the rest of Tennessee

Among the 95 Tennessee counties with data, Smith County is number 58 of 95 counting from the hardest. Across the whole country it is harder than 31% of counties.

Softest in Tennessee: Fayette County at 0.5 gpg. Hardest: Fentress County at 42.9 gpg. Closest to Smith County: Shelby County (4.8), Rhea County (5.1), DeKalb County (5.6).