Sinkhole risk in Washington County, IL: 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 Washington County

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

Across 563 square miles, under one square mile of Washington County maps onto soluble rock. With about 13,535 residents (24 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 359 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Washington County

The nearest county rated sinkhole country is Perry County, MO, about 49 miles southwest. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Clinton County, IL 17 mi north · 0% at surface
Perry County, IL 19 mi south · 0% at surface
Jefferson County, IL 27 mi east · 0% at surface
St. Clair County, IL 29 mi west · 0% at surface
Randolph County, IL 30 mi southwest · under 1% at surface
Marion County, IL 34 mi northeast · 0% at surface

Against the rest of Illinois

Washington County ranks 98 of 102 in Illinois for soluble rock at the surface, and sits above 0% of US counties on that measure.