SinkholeOdds

Sinkhole risk in Bexar County, TX: Pockets of it

Pockets of it

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

On soluble rock
42%
At or near the surface
42%
Buried under cover
0%

The next step for one property

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 523 of Bexar County's 1,240 square miles on soluble rock, 523 of them with the rock at or near the surface. With about 2,127,737 residents (1,715 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 275 map points about 2.1 miles apart, so a pocket smaller than that can be missed or overstated.

Read next: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Bexar County

The nearest county rated sinkhole country is Runnels County, TX, about 187 miles northwest. 3 of the 6 closest counties land in the same band; the ground changes quickly around here.

Which formation it is

The largest mapped soluble unit here is the Glen Rose Limestone (limestone), Early Cretaceous in age, covering about 13% of the county. Next is the Edwards Limestone at 10%.

The county also lies over the Gulf Coast salt domes, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Texas

Bexar County ranks 58 of 254 in Texas for soluble rock at the surface, and sits above 85% of US counties on that measure.