Sinkhole risk in Tarrant 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: 41%
At or near the surface: 41%
Buried under cover: 0%

What to do about a house in Tarrant County

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 354 of Tarrant County's 865 square miles on soluble rock, 354 of them with the rock at or near the surface. With about 2,230,708 residents (2,578 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 384 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Tarrant County

The nearest county rated sinkhole country is Baylor County, TX, about 125 miles northwest. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Johnson County, TX 27 mi south · 18% at surface
Dallas County, TX 30 mi east · 39% at surface
Parker County, TX 30 mi west · 21% at surface
Denton County, TX 32 mi north · 41% at surface
Wise County, TX 37 mi northwest · 24% at surface
Hood County, TX 39 mi southwest · 42% at surface

The rock underneath

The largest mapped soluble unit here is the Grayson Marl and Main Street Limestone, undivided (mudstone), Early Late Cretaceous and Late Early Cretaceous in age, covering about 15% of the county. Next is the Fort Worth Limestone and Duck Creek Formation, undivided at 9%.

Against the rest of Texas

Tarrant County ranks 61 of 254 in Texas for soluble rock at the surface, and sits above 84% of US counties on that measure.