Sinkhole risk in Castro County, TX: Not karst, but voids possible

Not karst, but voids possible

No soluble bedrock; some pseudokarst (piping or lava-tube ground).

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

What to do about a house in Castro County

Not true karst, but soil piping or lava tubes can still open voids - mention it to an inspector.

Across 894 square miles, under one square mile of Castro County maps onto soluble rock. With about 7,380 residents (8 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 396 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and how ground with no limestone still opens up.

Counties around Castro County

The nearest county rated sinkhole country is Briscoe County, TX, about 60 miles east. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Swisher County, TX 29 mi east · 0% at surface
Parmer County, TX 30 mi west · 0% at surface
Lamb County, TX 33 mi south · 0% at surface
Deaf Smith County, TX 34 mi northwest · under 1% at surface
Randall County, TX 36 mi northeast · 3% at surface
Hale County, TX 41 mi southeast · 0% at surface

Against the rest of Texas

Castro County ranks 164 of 254 in Texas for soluble rock at the surface, and sits above 0% of US counties on that measure.