Sinkhole risk in Sioux County, IA: No soluble rock mapped

No soluble rock mapped

No soluble bedrock mapped.

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

What to do about a house in Sioux County

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

Across 768 square miles, under one square mile of Sioux County maps onto soluble rock. With about 36,554 residents (48 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 352 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Sioux County

The nearest county rated sinkhole country is Knox County, NE, about 92 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Lyon County, IA 21 mi north · 0% at surface
Plymouth County, IA 24 mi south · 0% at surface
O'Brien County, IA 28 mi east · 0% at surface
Union County, SD 30 mi southwest · 0% at surface
Lincoln County, SD 31 mi northwest · 0% at surface
Osceola County, IA 34 mi northeast · 0% at surface

Against the rest of Iowa

Sioux County ranks 85 of 99 in Iowa for soluble rock at the surface, and sits above 0% of US counties on that measure.