Sinkhole risk in Aiken County, SC: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 72%
At or near the surface: 68%
Buried under cover: 4%

What this means before you buy

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 766 of Aiken County's 1,071 square miles on soluble rock, 726 of them with the rock at or near the surface. With about 179,245 residents (167 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 491 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Aiken County

The closest county with no soluble rock mapped is Saluda County, SC, about 32 miles north. None of the 6 closest counties land in the same band, so Aiken County stands out from its surroundings.

Barnwell County, SC 23 mi southeast · 45% at surface
Edgefield County, SC 25 mi northwest · 24% at surface
Richmond County, GA 29 mi southwest · 31% at surface
Lexington County, SC 31 mi northeast · 15% at surface
Saluda County, SC 32 mi north · under 1% at surface
Columbia County, GA 36 mi west · 10% at surface

Which formation it is

The largest mapped soluble unit here is the Huber/Lisbon/Barnwell Formations, undivided (sand), Eocene in age, covering about 68% of the county. Next is the Peedee Formation at 2%.

Against the rest of South Carolina

Aiken County ranks 11 of 46 in South Carolina for soluble rock at the surface, and sits above 92% of US counties on that measure.