Storm surge or flood: who pays for the water?

One house, two policies, three fights

When a hurricane puts water in your house, the first legal question is not how bad the damage is. It's which water. American property insurance splits hurricane damage between two entirely separate systems. Your homeowners policy covers wind: the roof the gusts opened, the rain that blew in through the opening, the tree that came through the wall. Your flood policy (if you have one) covers rising water: storm surge, overflowing rivers, ponding rain that entered at ground level.

The split is written into the homeowners policy as a water-damage exclusion, and the exclusion is written broadly. The standard language does not say "flood" and stop. It sweeps in waves, tidal water, spray, and overflow of any body of water, whether or not driven by wind. That last clause is aimed directly at storm surge, which is, physically, wind-driven ocean. Courts have enforced it as written.

STANDARD HOMEOWNERS WATER-DAMAGE EXCLUSION (ISO HO-3 FORM, TYPICAL WORDING)

"Water Damage means: Flood, surface water, waves, including tidal wave and tsunami, tides, tidal water, overflow of any body of water, or spray from any of these, all whether or not driven by wind…"

ANTI-CONCURRENT-CAUSATION (ACC) LEAD-IN · THE CLAUSE THE WHOLE WAR IS ABOUT

"We do not insure for loss caused directly or indirectly by any of the following. Such loss is excluded regardless of any other cause or event contributing concurrently or in any sequence to the loss."

Check your own policy against both boxes above. Exclusion wording varies by carrier and by form year, and, as the case law below shows, whether your policy carries the ACC lead-in can change the outcome of a mixed wind-and-water loss entirely.

On the other side of the split sits the National Flood Insurance Program. NFIP policies cover exactly what the homeowners policy excludes (rising water, surge included) but with hard federal limits: $250,000 for the building, $100,000 for contents, no coverage for additional living expenses at all. A surge loss bigger than the caps, or a surge loss at a house with no flood policy, lands in a gap where no insurer owes anything.

Who pays for what: the whole system on one chart

Read your loss against these three bands. Every hurricane water dispute is an argument about which band a given dollar of damage belongs in, because the bands have very different limits, deadlines, and defendants.

Two things follow from the chart. First, if your loss is mostly surge and exceeds the NFIP caps, the only way more insurance money exists is if part of the damage was wind, which is why policyholders fight to attribute damage to wind, and it is real money, not gamesmanship. Second, if you carried no flood policy, the carrier's incentive runs exactly opposite: every dollar attributed to water is a dollar nobody owes.

Katrina wrote the rules: Leonard, Corban, and Sebo

The modern wind-vs-water fight was built on the Mississippi coast after Katrina. Surge of 24-28 feet, the highest ever recorded in the U.S., scraped whole blocks to their slabs. Homeowners carriers attributed the losses to excluded surge; policyholders answered that 125-mph wind had destroyed their homes before the water arrived. With 1.7 million claims and roughly $41 billion in insured losses on the line, the argument went to the courts, and two decisions still frame every hurricane water denial today.

Leonard v. Nationwide Mut. Ins. Co., 499 F.3d 419 (5th Cir. 2007), the carrier's win. The Fifth Circuit held that the homeowners flood exclusion encompasses wind-driven storm surge, and that anti-concurrent-causation clauses are enforceable as written: where excluded water and covered wind combine to cause a loss, the ACC lead-in lets the exclusion control the combined damage. Leonard closed the argument that "surge isn't flood," and made the ACC clause the industry's favorite paragraph.

Corban v. United Servs. Auto. Ass'n, 20 So. 3d 601 (Miss. 2009), the policyholder's counterweight. The Mississippi Supreme Court held that the ACC clause applies only where wind and water act contemporaneously and in conjunction to cause the same damage. Wind damage that was complete before the surge arrived is a covered loss the moment it happens, and no later flood can un-cover it. And critically: the insurer bears the burden of proving that excluded water, not covered wind, caused the loss.

Sebo v. American Home Assurance Co., 208 So. 3d 694 (Fla. 2016), Florida's rule for policies without ACC wording. Where covered and excluded perils converge and no single cause is the sole proximate cause of the loss, the Florida Supreme Court applied the concurrent-cause doctrine: coverage may exist for the combined loss. The court noted the carrier could have drafted ACC language, and for other exclusions in the same policy did. The lesson cuts both ways: in Florida the exact wording of your exclusion decides which doctrine applies, so read the policy, not the denial letter's paraphrase of it.

Katrina litigation also surfaced the structural conflict that Congress later investigated: most NFIP policies are adjusted by private "Write Your Own" carriers, often the same company holding the wind policy on the same house. Every dollar steered to the federally backed flood policy was a dollar off the carrier's own wind exposure. That conflict remains a standing policyholder argument for demanding both complete claim files.

Slab cases: when the evidence washed away

The hardest version of the fight is the slab case: the house is simply gone. No roof to read for uplift, no walls to read for a water line, just a concrete pad and a debris field. Katrina created thousands of them on the Mississippi coast; Ian created a new generation on Fort Myers Beach and Sanibel, where rows of homes along Estero Boulevard were removed to the slab.

With the physical evidence destroyed, slab cases turn on burden of proof and reconstruction. Under Corban-line reasoning, the insurer invoking the flood exclusion must prove excluded water caused the loss; it cannot simply presume surge because the neighborhood flooded. Policyholders rebuild the sequence from what survives: recorded wind speeds before the surge peak, the direction debris traveled, which way structures fell, surviving neighbors' accounts, and engineering analysis of the foundation and connections. A house that took 150-mph wind for an hour before the water arrived has a wind story to tell even from a bare slab.

Practical rule from two decades of slab litigation: never let the site be cleared before it is documented. Photograph the slab, the debris field, and the neighboring structures from every angle before cleanup. Once the debris is hauled away, the carrier's "100% surge" theory has nothing left to contradict it.

Ian: the Florida surge litigation wave

Hurricane Ian put the Katrina playbook to work in Florida at scale. A high-end Category 4 at Cayo Costa with 10-15 feet of surge across Fort Myers Beach, Sanibel, and Estero Island, Ian generated over 770,000 claims across all lines and $112.9 billion in damage, the costliest hurricane in Florida history. On the barrier islands, carriers attributed slab-only and first-floor losses to excluded surge, pushing recovery toward NFIP policies with their $250,000 caps, or toward nothing, where owners carried no flood coverage.

The closure numbers drew regulatory attention: of 565,101 residential claims in FLOIR's data, 157,445, roughly 28 percent, were closed without payment. Carriers cited flood exclusions, below-deductible damage, and duplicate filings. Policyholder attorneys cited the same numbers as evidence of systematic underpayment, and Florida regulators later fined multiple insurers over Ian claims-handling failures.

Where the fights reached juries, policyholders showed the wind story could win. In Lee County, jurors awarded $518,225 to the owners of a demolished Fort Myers Beach home under their wind policy, agreeing that Category 4 wind alone would have caused the total loss, against SafePoint Insurance's surge defense, and $248,000 to nearby owners in a parallel verdict against Homeowners Choice. Both claims had originally been denied as flood damage. The verdicts are the current, Florida-specific proof of the oldest rule in this fight: "the water did it" is a theory that must be proven, not a fact the carrier gets for free.

Helene → Milton: two storms, thirteen days, one house

The 2024 season added a third dimension to the causation war: which storm. Helene pushed record surge into the Pinellas barrier islands and Tampa Bay on September 26. Thirteen days later, Milton crossed many of the same neighborhoods with Category 3 wind, 5-10 feet of new surge to the south, and 18+ inches of rain, while Helene's flood debris still sat at the curb.

For a house that took Helene's water and Milton's wind, three questions controlled the payout: which storm caused which damage, which policy (homeowners vs. flood) responds to each, and how many hurricane deductibles apply. Florida's percentage deductible runs per-season in some policy forms and per-storm in others. Flood carriers pointed at Milton's wind; wind carriers pointed at Helene's water; each storm's file blamed the other's.

The aggregate result, per FLOIR's November 2024 data: of 329,000+ residential claims across the two storms, 42 percent were closed without payment, with below-deductible losses and uncovered flood damage the leading cited reasons. The single strongest piece of evidence in the allocation disputes turned out to be anything dated inside the 13-day gap: photos of the property after Helene but before Milton, adjuster inspections, contractor estimates. Owners who documented between the storms could draw the line; owners who couldn't watched both carriers draw it for them.

Building the sequence evidence

Every doctrine above (ACC, concurrent cause, burden of proof) resolves on the same factual question: what did the wind do before the water arrived, and how high did the water actually get? Four public evidence sources answer it, and all four are free.

USGS high-water marks: USGS Flood Event Viewer ↗ · NHC reports and surge maps: NHC Tropical Cyclone Reports ↗ · wind history for your address: our Storm History Lookup.

NFIP claim mechanics vs. private flood

If part of your loss lands in the flood band, understand that an NFIP claim is a different legal animal from a homeowners claim. It runs on federal rules, and the traps are procedural.

The 60-day sworn proof of loss is the trap that has voided more flood claims than any adjuster's opinion. After Sandy, unfiled and late proofs of loss defeated otherwise valid claims wholesale. The one-year federal suit deadline runs from the first written denial of any part of the claim, and courts apply it strictly. And because federal law preempts state remedies, there is no bad-faith leverage against an NFIP carrier: the claim is won on documentation or not at all. Private flood policies, a growing market in Florida, trade the federal backstop for ordinary insurance law: higher limits, ALE, replacement-cost contents, and state-law remedies when the carrier misbehaves.

Florida vs. South Carolina

Deadlines shown are general rules as of July 2026 and have exceptions: supplemental claims, reopened claims, and policy-specific notice provisions can shorten them. NFIP deadlines are federal and identical in both states. Verify against your policy and current statute.

Surge vs. flood: the questions everyone asks

Independent informational resource, not legal advice. Case summaries and statutes are drafted for education and have not been verified by counsel; consult an attorney about your specific claim. FLOIR claim statistics as reported in the agency's catastrophe data releases.