Sinkhole risk in Blanco 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: 90%
At or near the surface: 90%
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 637 of Blanco County's 709 square miles on soluble rock, 637 of them with the rock at or near the surface. With about 13,358 residents (19 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 266 map points about 1.6 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 Blanco County

The nearest county rated sinkhole country is Runnels County, TX, about 144 miles northwest. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Hays County, TX 26 mi southeast · 88% at surface
Kendall County, TX 29 mi southwest · 98% at surface
Comal County, TX 32 mi south · 92% at surface
Gillespie County, TX 33 mi west · 89% at surface
Llano County, TX 35 mi northwest · 11% at surface
Burnet County, TX 38 mi north · 63% at surface

The rock underneath

The largest mapped soluble unit here is the Glen Rose Limestone (limestone), Early Cretaceous in age, covering about 57% of the county. Next is the Hensell Sand at 8%.

Against the rest of Texas

Blanco County ranks 13 of 254 in Texas for soluble rock at the surface, and sits above 97% of US counties on that measure.