Sinkhole risk in Fayette County, IA: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock: 100%
At or near the surface: 19%
Buried under cover: 82%

What to do about a house in Fayette County

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 731 of Fayette County's 731 square miles on soluble rock, 135 of them with the rock at or near the surface. With about 19,152 residents (26 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 399 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Fayette County

The nearest county rated sinkhole country is Clayton County, IA, about 26 miles east, close enough that the same rock may run under the county line. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Bremer County, IA 25 mi west · 0% at surface
Clayton County, IA 26 mi east · 54% at surface
Buchanan County, IA 27 mi south · 0% at surface
Chickasaw County, IA 28 mi northwest · 0% at surface
Winneshiek County, IA 30 mi north · 18% at surface
Black Hawk County, IA 36 mi southwest · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Cedar Valley Limestone (limestone), Middle Dovonian in age, covering about 35% of the county. Next is the Niagaran Series at 33%.

Against the rest of Iowa

Fayette County ranks 5 of 99 in Iowa for soluble rock at the surface, and sits above 74% of US counties on that measure.