How hard is the water in Grundy County, TN?

3.3 grains per gallon

You do not need a softener here.

The median hardness measured in Grundy County, TN is 56 mg/L as calcium carbonate, which is 3.3 gpg. That is soft on the USGS scale. It comes from 166 samples at 30 sites between 1990 and 2019, drawn from every sampling site in the county, wells and surface water together.

How much it varies here

Half the sites came in between 2.1 and 6.1 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

You can skip the softener. At 3.3 gpg the most a softener would fix is the odd water spot. If a salesperson in Grundy County says otherwise, ask to see their reading in grains per gallon and compare it with this one. Because Grundy 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 0.1 to 12.3 gpg

The softest single sample on record in Grundy County was 1.7 mg/L and the hardest 210 mg/L, a 124-fold gap. The top quarter of sites read above 6.1 gpg and the bottom quarter below 2.1 gpg. So even in a soft county, a handful of wells here produce water hard enough to scale a heater.

Wells 6.2 gpg, rivers and lakes 3.1 gpg

2 groundwater samples from 1 wells put the median at 105.5 mg/L. 164 surface samples from 29 sites put it at 53 mg/L. In Grundy County the wells come out 3.1 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.

Grundy County against the rest of Tennessee

Among the 95 Tennessee counties with data, Grundy County is number 67 of 95 counting from the hardest. Across the whole country it is harder than 23% of counties.

Softest in Tennessee: Fayette County at 0.5 gpg. Hardest: Fentress County at 42.9 gpg. Closest to Grundy County: Marion County (3.2), Moore County (3.2), Scott County (3.3).