Sinkhole risk in Comal 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: 92%
At or near the surface: 92%
Buried under cover: 0%

What this means before you buy

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 513 of Comal County's 560 square miles on soluble rock, 513 of them with the rock at or near the surface. With about 201,628 residents (360 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 490 map points about 1.1 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 Comal County

The nearest county rated sinkhole country is Runnels County, TX, about 174 miles northwest. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Hays County, TX 22 mi northeast · 88% at surface
Guadalupe County, TX 24 mi southeast · 9% at surface
Kendall County, TX 29 mi west · 98% at surface
Bexar County, TX 30 mi southwest · 42% at surface
Blanco County, TX 32 mi north · 90% at surface
Caldwell County, TX 38 mi east · 8% at surface

The rock underneath

The largest mapped soluble unit here is the Glen Rose Limestone (limestone), Early Cretaceous in age, covering about 51% of the county. Next is the Edwards Limestone at 30%.

Against the rest of Texas

Comal County ranks 11 of 254 in Texas for soluble rock at the surface, and sits above 97% of US counties on that measure.