Sinkhole risk in Polk County, GA: Sinkhole country

Sinkhole country

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

On soluble rock: 66%
At or near the surface: 66%
Buried under cover: 0%

The next step for one property

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

That works out to roughly 204 of Polk County's 310 square miles on soluble rock, 204 of them with the rock at or near the surface. With about 44,610 residents (144 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 320 map points about 1.0 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 Polk County

The closest county with no soluble rock mapped is Haralson County, GA, about 14 miles south. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Haralson County, GA 14 mi south · 0% at surface
Floyd County, GA 19 mi north · 64% at surface
Paulding County, GA 19 mi east · under 1% at surface
Bartow County, GA 26 mi northeast · 62% at surface
Cherokee County, AL 27 mi west · 57% at surface
Cleburne County, AL 29 mi southwest · 2% at surface

What Polk County is built on

The largest mapped soluble unit here is the Knox Group undifferentiated (dolostone (dolomite)), Ordovician-Cambrian in age, covering about 44% of the county. Next is the Newala Limestone at 18%.

Against the rest of Georgia

Polk County ranks 12 of 159 in Georgia for soluble rock at the surface, and sits above 91% of US counties on that measure.