Sinkhole risk in Washington County, NC: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock: 11%
At or near the surface: 11%
Buried under cover: 0%

The next step for one property

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 37 of Washington County's 347 square miles on soluble rock, 37 of them with the rock at or near the surface. With about 10,654 residents (31 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 279 map points about 1.1 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 Washington County

The nearest county rated sinkhole country is Bertie County, NC, about 26 miles northwest, 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.

Chowan County, NC 20 mi north · 15% at surface
Tyrrell County, NC 23 mi east · 0% at surface
Perquimans County, NC 25 mi north · 3% at surface
Bertie County, NC 26 mi northwest · 68% at surface
Beaufort County, NC 29 mi southwest · 41% at surface
Martin County, NC 31 mi west · 84% at surface

Which formation it is

The largest mapped soluble unit here is the Yorktown Formation and Duplin Formation, Undivided (clay or mud), Tertiary in age, covering about 11% of the county.

Against the rest of North Carolina

Washington County ranks 39 of 100 in North Carolina for soluble rock at the surface, and sits above 68% of US counties on that measure.