How hard is the water in Clarendon County, SC?

1.1 grains per gallon

You do not need a softener here.

The median hardness measured in Clarendon County, SC is 20 mg/L as calcium carbonate, which is 1.1 gpg. That is soft on the USGS scale. It comes from 2,326 samples at 42 sites between 1990 and 2025, drawn from every sampling site in the county, wells and surface water together.

How much it varies here

Half the sites came in between 1.1 and 1.4 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: high (how it is measured).

What to do next

You can skip the softener. At 1.1 gpg the most a softener would fix is the odd water spot. If a salesperson in Clarendon 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 0.5 to 3.6 gpg

The softest single sample on record in Clarendon County was 8.2 mg/L and the hardest 61 mg/L, a 7-fold gap. The top quarter of sites read above 1.4 gpg and the bottom quarter below 1.1 gpg.

Wells 1.4 gpg, rivers and lakes 1.1 gpg

3 groundwater samples from 1 wells put the median at 24.4 mg/L. 2,323 surface samples from 41 sites put it at 19.5 mg/L. In Clarendon County the wells come out 0.3 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.

Clarendon County against the rest of South Carolina

Among the 46 South Carolina counties with data, Clarendon County is number 25 of 46 counting from the hardest. Across the whole country it is harder than 8% of counties.

Softest in South Carolina: Aiken County at 0.2 gpg. Hardest: Georgetown County at 15.2 gpg. Closest to Clarendon County: Calhoun County (1.2), Cherokee County (1.1), Saluda County (1.2).