At a glance
| Reported incidents | 4,457 (FGS, September 2026) |
|---|---|
| Verified sinkholes | 103 |
| Most reports | Hillsborough, Marion, Citrus |
| Always covered | Catastrophic ground cover collapse |
| Optional | Sinkhole loss coverage |
| FGS helpline | 850-245-2118 |
What is causing the sinkholes in Florida?
The Florida Geological Survey (FGS), part of the Department of Environmental Protection, explains that most of Florida sits on limestone and dolomite. Rainwater is slightly acidic and becomes more so as it passes through decaying plants. Over long periods it dissolves the porous limestone, leaving underground voids. When the sand and clay above a void can no longer hold, it settles or collapses into it and a sinkhole forms at the surface. This kind of terrain is called karst, and it also produces Florida's springs, caves and disappearing streams.
Triggers
The FGS homeowner leaflet lists changes in the water table from drought or heavy rain, heavy groundwater pumping, drainage from lakes and stormwater ponds, and land clearing, heavy loads and excavation. Activity is greatest when a drought ends and heavy rain returns. Two FGS examples: Tropical Storm Debby in 2012 left more than 300 documented sinkholes, and 11 days of freeze-protection pumping around Plant City in January 2010 lowered the aquifer 60 feet and produced over 150 sinkholes.
Not every hole is a sinkhole
The FGS lists common look-alikes: broken water mains, storm drains or sewer lines, collapsed septic tanks, rotting tree stumps and roots, buried construction debris, poorly compacted fill and erosion from roof or driveway runoff. A depression not confirmed by a licensed professional geologist is recorded as a subsidence incident, not a sinkhole.
The three types of Florida sinkhole
Cover-collapse
Sediment over a void in the rock gives way suddenly and opens a hole at the surface. This is the dramatic kind that makes the news. The FGS says the initial hole may keep growing for minutes to days, and the sides can slump for about a day.
Cover-subsidence
Where thick, permeable sand covers the limestone, grains ravel slowly down into the void. The surface shows a gentle bowl-shaped depression that forms over years or longer.
Solution
Where there is little or no cover over the limestone, the rock dissolves at or near the surface, often along joints and cracks.
Where in Florida are the most sinkholes?
The FGS keeps the state's only public database of reported subsidence incidents. As of September 25, 2026 it held 4,457 reports statewide. These are the counties with the most reports.
| County | Subsidence incident reports |
|---|---|
| Hillsborough | 618 |
| Marion | 489 |
| Citrus | 450 |
| Pasco | 345 |
| Hernando | 315 |
| Polk | 304 |
| Orange | 232 |
| Suwannee | 213 |
| Lake | 178 |
| Seminole | 172 |
| Leon | 155 |
| Pinellas | 121 |
How to read these numbers
The FGS is clear about the limits. Reports are voluntary and come mostly from the State Watch Office, the public and emergency surveys. Only 103 of the 4,457 records are marked as verified true sinkholes; most have never been checked by a geologist. Reports also cluster where people live and roads are, because that is where holes get seen. Treat the list as a map of where incidents are reported, not a risk rating. If you are looking at homes in these counties, our Tampa, Lakeland and Clermont guides cover Hillsborough, Polk and Lake.
"Sinkhole alley"
The Southwest Florida Water Management District describes sinkholes as common across west-central Florida, and the Tampa Bay counties of Hillsborough, Pasco and Hernando, with Citrus, Marion and Polk, lead the report counts. The FGS explains why: risk is higher where limestone is close to the surface, or where the water table, layers of sediment and the aquifer combine in the right way.
Is Florida in danger of sinkholes?
The FGS says that since the whole state sits on carbonate rock, a sinkhole could in theory form anywhere, but that most underground cavities will never collapse in our lifetimes and most people are never affected. It also says there is no ready way to predict where one will form.
When was the last sinkhole in Florida?
They are reported every few days. The FGS database includes reports from Marion, Suwannee, Alachua, Pasco and Palm Beach counties in September 2026 alone, the latest dated September 16, most not yet verified. Search the database on DEP's Map Direct site or open data portal for the newest records near an address.
Sinkhole insurance in Florida
Florida law, section 627.706 of the Florida Statutes, splits ground movement into two very different coverages. Knowing which one a policy has matters more than anything else on this page.
Catastrophic ground cover collapse: included
Every insurer authorized to write property insurance in Florida must cover catastrophic ground cover collapse. The statute sets four conditions: the ground abruptly collapses, there is a depression clearly visible to the naked eye, the building (including the foundation) is structurally damaged, and a government agency condemns the building and orders it vacated. Settling or cracking of a foundation alone does not qualify.
Sinkhole loss: optional, extra premium
Insurers must make sinkhole loss coverage available for an extra premium. It covers structural damage caused by sinkhole activity even without a condemned building. The insurer may require an inspection first and may offer a sinkhole deductible of 1%, 2%, 5% or 10% of the dwelling limit, with a premium discount for each. Policies without it must state in bold type that only catastrophic ground cover collapse is covered.
What "structural damage" means
The statute defines it narrowly: floor or foundation movement beyond building code tolerances that makes the structure unfit or unsafe, walls leaning out of plumb beyond set limits, a real risk of imminent collapse, or substantial structural damage under the Florida Building Code. Cosmetic cracks are not enough.
If you file a sinkhole claim
Under section 627.7073, the professional engineer or professional geologist who tests the property must issue a report and certification to both the insurer and the policyholder, and the insurer files a copy with the Clerk of Court in the county. If you and the insurer disagree, section 627.706 points to neutral evaluation: an alternative dispute process run by an engineer or geologist with sinkhole expertise who has completed training approved by the Department of Financial Services.
Citizens
Citizens Property Insurance includes catastrophic ground cover collapse in certain policies and treats sinkhole loss as optional on most. It can require a sinkhole inspection first, and sinkhole cover cannot be added in the middle of a policy term, so ask before renewal.
Buying a home in a sinkhole area
What the seller must disclose
Under section 627.7073, a seller must tell a buyer if a sinkhole claim was made and paid on the property, and whether the money was used to repair the damage. The FGS notes that most Florida disclosure forms also ask about earth movement in general. If it is missing, ask.
Checking the property
The FGS says home inspectors and insurance adjusters are not trained to find sinkhole activity. A licensed professional geologist, or an engineering firm with one on staff, can run ground-penetrating radar, resistivity surveys and soil borings, but results are not always conclusive and the cost is often beyond a typical budget. A search of the subsidence database near the address and a look at the property's insurance claim history are cheap first steps. Add these to your Florida home inspection checklist.
Homes with a repaired sinkhole
Engineering firms repair sinkholes with grout or foam injection, or with piers and pins. The FGS view is that a repair certified by a licensed engineer and completed to the insurer's satisfaction is likely sound, but no natural system comes with a guarantee. Ask for the engineer's report, the repair certification and the insurer's closing letter. By law the sinkhole testing report is also filed with the county Clerk of Court.
Getting insured
The FGS notes that insurers may decline a home because of sinkholes within a set distance, and each company defines that distance differently. If one declines, others may not. Get quotes early in your inspection period. Our Florida homeowners insurance guide explains how to compare insurers by county.
Warning signs and what to do
Signs of a forming sinkhole
The FGS leaflet lists cracks in soil, sagging ground, soil slumping, exposed rock, dead or dying plants in a patch, and trees, fences or structures that begin to lean.
If a hole opens in your yard
Mark it and keep people and pets away. Do not put water in it, because that can enlarge it. Small holes away from buildings can often be filled with clean sand or clayey sand; never use trash or anything that could pollute the aquifer. If the hole is under or near the house or pool, or walls are cracking or sagging, stay out and call your insurer at once. If life is at risk, call 911.
Who to call
No state agency inspects sinkholes on private property. The FGS runs a Sinkhole Helpline at 850-245-2118 staffed to answer questions, and it asks owners to file a subsidence incident report. Insurance questions go to the Department of Financial Services at 1-877-693-5236. In some areas the water management district or county emergency management office will help assess a hole.
Reducing the risk at home
The FGS suggests fixing plumbing leaks promptly, directing downspouts away from the house, avoiding overwatering, and filling low spots so water does not pool.
Common questions
Where in Florida are the most sinkholes?+
Reports cluster in west-central Florida. In the Florida Geological Survey's subsidence database, Hillsborough has the most reports (618), followed by Marion (489), Citrus (450), Pasco (345), Hernando (315) and Polk (304). Most reports are unverified, and they concentrate where people live, so treat the ranking as reporting activity rather than a precise risk map.
Is Florida in danger of sinkholes?+
Sinkholes are a natural part of Florida's limestone landscape, and the Florida Geological Survey says one could in theory form anywhere in the state. It also says most underground cavities will never collapse in our lifetimes and most people are never affected. Risk is higher where limestone is near the surface, especially in west-central Florida.
What is causing the sinkholes in Florida?+
Slightly acidic groundwater slowly dissolves Florida's limestone, creating voids. Sand and clay above a void eventually settle or collapse into it. Drought followed by heavy rain, heavy groundwater pumping, drainage ponds, land clearing and construction loads can trigger a collapse. Broken pipes, septic tanks and rotting stumps can also make holes that look like sinkholes.
When was the last sinkhole in Florida?+
New reports arrive every few days. As of late September 2026, the Florida Geological Survey's database included reports from several counties that month, the latest dated September 16, 2026 in Marion County. Most reports have not been verified by a geologist. Search DEP's Map Direct site for the newest records near a specific address.
Does homeowners insurance cover sinkholes in Florida?+
Every Florida homeowners policy from an authorized insurer covers catastrophic ground cover collapse, which requires an abrupt collapse, a visible depression, structural damage and a government order to vacate. Damage from gradual sinkhole activity is covered only if you buy optional sinkhole loss coverage, which costs extra and may need an inspection.
Should I buy a house with a repaired sinkhole?+
It can be reasonable if the repair was certified by a licensed engineer and completed to the insurer's satisfaction, which the Florida Geological Survey says is likely sound, though no repair is guaranteed. Get the engineer's report, repair certification and claim history, confirm the seller's disclosure, and get an insurance quote before your inspection period ends.
Sources
- Florida DEP / Florida Geological Survey: Sinkholes
- Florida DEP / Florida Geological Survey: Sinkhole FAQ
- Florida Geological Survey: Leaflet 20, A Homeowner's Guide to Sinkholes
- Florida DEP: Subsidence Incident Reports
- Florida DEP open data: Florida Subsidence Incident Reports (queried September 25, 2026)
- Southwest Florida Water Management District: Sinkholes
- Florida Statutes s. 627.706: Sinkhole insurance; catastrophic ground cover collapse
- Citizens Property Insurance: Inspections (sinkhole coverage)