How hard is the water in Fentress County, TN?
42.9 grains per gallon
A softener will pay its way here.
The median hardness measured in Fentress County, TN is 735 mg/L as calcium carbonate, which is 42.9 gpg. That is very hard on the USGS scale. It comes from 6 samples at 5 sites between 1991 and 2016, 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 28.1 and 136.7 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: medium (how it is measured).
What to do next
At 42.9 gpg a softener pays its way here. Before you buy, check the quoted unit's grain capacity against the sizing table below, and ask whether it regenerates on demand, which uses less salt than a timer. Call your utility for its own report if you are on city water.
More on sizing a softener for your household.
From 13.2 to 137.3 gpg
The softest single sample on record in Fentress County was 226 mg/L and the hardest 2,350 mg/L, a 10-fold gap. The top quarter of sites read above 136.7 gpg and the bottom quarter below 28.1 gpg.
Wells 42.9 gpg, rivers and lakes 6.4 gpg
6 groundwater samples from 5 wells put the median at 735 mg/L. 198 surface samples from 14 sites put it at 110 mg/L. In Fentress County the wells come out 36.5 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. A utility here that draws from the river can deliver noticeably different water from a private well next door.
What a softener would cost to run
For a household of 3, a 64,000-grain unit covers a week between regenerations. Expect about 938 lb of salt a year (24 bags of 40 lb, about $169), 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 $269 a year.
Sizing at 42.9 gpg
| People | Grains a day | Unit | Salt a year |
|---|---|---|---|
| 1 | 2,574 | 24,000 | 313 lb |
| 2 | 5,148 | 40,000 | 626 lb |
| 4 | 10,296 | 80,000 | 1,253 lb |
| 6 | 15,444 | twin tank | 1,879 lb |
Fentress County against the rest of Tennessee
Among the 95 Tennessee counties with data, Fentress County is the hardest. Across the whole country it is harder than 97% of counties.
Softest in Tennessee: Fayette County at 0.5 gpg. Closest to Fentress County: Williamson County (28.6), Marshall County (17.7), Maury County (17.2).