SinkholeOdds

Sinkhole risk in Volusia County, FL: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock
87%
At or near the surface
22%
Buried under cover
65%

What to do about a house in Volusia County

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

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 962 of Volusia County's 1,101 square miles on soluble rock, 247 of them with the rock at or near the surface. With about 602,772 residents (547 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 406 map points about 1.6 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 Volusia County

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

What Volusia County is built on

The largest mapped soluble unit here is the Shelly sediments of Plio-Pleistocene age (beach sand), Holocene in age, covering about 58% of the county. Next is the Shelly sediments of Plio-Pleistocene age at 12%.

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

Volusia County ranks 47 of 67 in Florida for soluble rock at the surface, and sits above 76% of US counties on that measure.