Sinkhole risk in Salt Lake County, UT: 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: 15%
At or near the surface: 15%
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 111 of Salt Lake County's 753 square miles on soluble rock, 111 of them with the rock at or near the surface. With about 1,216,274 residents (1,616 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 252 map points about 1.7 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Salt Lake County

The nearest county rated sinkhole country is Emery County, UT, about 131 miles southeast. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Davis County, UT 29 mi northwest · under 1% at surface
Morgan County, UT 34 mi northeast · 9% at surface
Utah County, UT 40 mi south · 22% at surface
Weber County, UT 42 mi north · 9% at surface
Wasatch County, UT 46 mi southeast · 18% at surface
Summit County, UT 52 mi east · 6% at surface

What Salt Lake County is built on

The largest mapped soluble unit here is the Pennsylvanian and Permian sedimentary rocks in central Utah (sandstone), Pennsylvanian to Permian in age, covering about 6% of the county. Next is the Jurassic (1) sedimentary rocks in Salt Lake City-Coalville-Randolph region at 3%.

3% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

Against the rest of Utah

Salt Lake County ranks 9 of 29 in Utah for soluble rock at the surface, and sits above 71% of US counties on that measure.