How hard is the water in DeKalb County, GA?

2.2 grains per gallon

You do not need a softener here.

The median hardness measured in DeKalb County, GA is 38 mg/L as calcium carbonate, which is 2.2 gpg. That is soft on the USGS scale. It comes from 10 samples at 10 sites between 1994 and 2025, 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 0.9 and 2.8 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

You can skip the softener. At 2.2 gpg the most a softener would fix is the odd water spot. If a salesperson in DeKalb County says otherwise, ask to see their reading in grains per gallon and compare it with this one.

More on when a softener is not worth it.

From 0.0 to 4.5 gpg

The softest single sample on record in DeKalb County was 0.8 mg/L and the hardest 76.2 mg/L, a 95-fold gap. The top quarter of sites read above 2.8 gpg and the bottom quarter below 0.9 gpg.

Wells 2.2 gpg, rivers and lakes 2.1 gpg

10 groundwater samples from 10 wells put the median at 38.4 mg/L. 2,808 surface samples from 62 sites put it at 36.5 mg/L. In DeKalb County the wells come out 0.1 gpg harder. Groundwater sits in contact with rock for years and picks up calcium and magnesium as it goes, so wells usually read harder. The two sources are close, so the county figure should hold whichever one your tap is on.

DeKalb County against the rest of Georgia

Among the 159 Georgia counties with data, DeKalb County is number 38 of 159 counting from the hardest. Across the whole country it is harder than 17% of counties.

Softest in Georgia: Richmond County at 0.2 gpg. Hardest: Glynn County at 13.6 gpg. Closest to DeKalb County: Burke County (2.2), Cobb County (2.1), Dooly County (2.1).