Sinkhole risk in Salem County, NJ: Pockets of it

Pockets of it

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

On soluble rock: 15%
At or near the surface: 15%
Buried under cover: 0%

What to do about a house in Salem 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 50 of Salem County's 332 square miles on soluble rock, 50 of them with the rock at or near the surface. With about 65,874 residents (198 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 473 map points about 0.8 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Salem County

The nearest county rated sinkhole country is Washington County, MD, about 131 miles west. None of the 6 closest counties land in the same band, so Salem County stands out from its surroundings.

Gloucester County, NJ 15 mi northeast · 9% at surface
New Castle County, DE 15 mi west · under 1% at surface
Cumberland County, NJ 21 mi southeast · 0% at surface
Delaware County, PA 24 mi north · 0% at surface
Camden County, NJ 26 mi northeast · 6% at surface
Cecil County, MD 31 mi west · 0% at surface

What Salem County is built on

The largest mapped soluble unit here is the Mt. Laurel Formation (sand), Upper Cretaceous, upper Campanian in age, covering about 9% of the county. Next is the Vincentown Formation at 6%.

Against the rest of New Jersey

Salem County ranks 1 of 21 in New Jersey for soluble rock at the surface, and sits above 71% of US counties on that measure.