SinkholeOdds

Sinkhole risk in Broward County, FL: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock
99%
At or near the surface
99%
Buried under cover
0%

What to do about a house in Broward County

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

Standard Florida homeowners policies cover only catastrophic ground cover collapse; full sinkhole coverage is a separately priced option insurers must offer.

That works out to roughly 1,190 of Broward County's 1,203 square miles on soluble rock, 1,190 of them with the rock at or near the surface. With about 2,037,472 residents (1,694 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 378 map points about 1.8 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: what Florida insurers have to cover, and why gypsum and salt move faster than limestone.

Counties around Broward County

The closest county with no soluble rock mapped is Gulf County, FL, about 387 miles northwest. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Which formation it is

The largest mapped soluble unit here is the Shelly sediments of Plio-Pleistocene age (limestone), Pliocene/Pleistocene in age, covering about 52% of the county. Next is the Miami Limestone at 47%.

The county also lies over the Floridan shelf, 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 Florida

Broward County ranks 1 of 67 in Florida for soluble rock at the surface, and sits above 99% of US counties on that measure.