How hard is the water in Montgomery County, TN?
8.6 grains per gallon
A softener is worth it here.
The median hardness measured in Montgomery County, TN is 148 mg/L as calcium carbonate, which is 8.6 gpg. That is hard on the USGS scale. It comes from 31 samples at 5 sites between 1990 and 2023, 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 8.5 and 9.7 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 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 7.5 to 10.6 gpg
The softest single sample on record in Montgomery County was 128 mg/L and the hardest 181 mg/L, a 1-fold gap. The top quarter of sites read above 9.7 gpg and the bottom quarter below 8.5 gpg.
Wells 8.6 gpg, rivers and lakes 10 gpg
31 groundwater samples from 5 wells put the median at 148 mg/L. 566 surface samples from 38 sites put it at 172 mg/L. In Montgomery County the rivers and lakes come out 1.4 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 189 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 |
Montgomery County against the rest of Tennessee
Among the 95 Tennessee counties with data, Montgomery County is number 36 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 Montgomery County: Overton County (8.6), Blount County (8.7), Cannon County (8.7).