A Florida property manager in Collier County filed a wind claim after Hurricane Ian. The roof was shredded. Interior ceilings had collapsed. Water had poured in through failed openings for hours before the surge arrived. The insurer denied the entire claim — citing a single paragraph buried in the exclusions: the anti-concurrent causation clause. The argument was that flood, an excluded peril, had also contributed to the loss. Therefore, nothing was owed.

This scenario plays out thousands of times after every major Florida hurricane. Understanding the concurrent causation doctrine — what it is, how insurers use it, and how to fight it — is one of the most important things a Florida property manager can know before storm season.

What Concurrent Causation Means

Concurrent causation occurs when two or more perils contribute to the same loss. In Florida hurricanes, the typical combination is wind (a covered peril under most landlord and homeowner policies) and storm surge or flooding (universally excluded from property policies — covered only by separate NFIP or private flood policies).

The causation dispute arises when both perils affect the same property in the same storm. A Cat 4 hurricane makes landfall. Wind strips the roof. Rain pours in. Hours later, surge water enters through the same openings. By the time the damage is assessed, the property has been hit by two forces: one covered, one excluded. Now comes the legal question: who pays?

Under pure concurrent causation doctrine — the older rule — if a covered peril contributed to the loss at all, coverage applied. But the insurance industry responded by adding the anti-concurrent causation (ACC) clause to policy language. That clause flipped the outcome entirely.

The Anti-Concurrent Causation Clause: How It Works

The ACC clause typically appears in the water damage or flood exclusion section of a DP-3 landlord policy or HO-3 homeowner policy. The language varies by carrier but the operative effect is the same: if an excluded peril contributed to the loss — in any sequence, regardless of whether it was the primary cause — the entire claim may be denied.

A representative version reads: "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." Flood, surface water, tidal wave, storm surge, and similar perils are then listed.

// KEY RISK

The ACC clause does not require flood to be the primary or even a major cause of the loss. It requires only that flood contributed in any way. In a hurricane where surge follows wind, an insurer can argue that the sequence itself — wind first, surge second — means the excluded peril was part of the same event. That argument, if accepted, eliminates all coverage regardless of how much pure wind damage existed.

Why This Matters More in Florida Than Other States

Florida's geography makes concurrent causation disputes uniquely common and uniquely consequential. The combination of factors is nearly unique in the U.S.:

  • Coastal exposure: A large share of Florida rental property inventory sits within FEMA-designated flood zones where storm surge is foreseeable in major storms.
  • Hurricane intensity: Cat 3–5 storms produce both extreme wind and extreme surge. Ian produced 15-foot surge in some areas of Lee County while also generating 150+ mph winds. Both perils damaged the same buildings simultaneously.
  • Flood coverage gap: Most Florida rental property owners carry no NFIP or private flood policy. Standard Citizens and private landlord policies cover wind only. When both wind and surge cause damage, the ACC clause can eliminate the one coverage the property owner actually purchased.
  • High property values: Florida coastal and near-coastal rental properties often have insured values of $300,000–$800,000+. An ACC denial in that range is financially catastrophic.

The Three Damage Scenarios — and What Each Means for Your Claim

Scenario 1: Wind damage only, surge did not reach the property

This is the cleanest scenario. If NOAA inundation maps, local survey data, and forensic evidence all confirm that surge did not reach your property, the ACC clause has no foothold. Document this evidence — surge maps, neighbor statements, photos with tide lines or debris patterns — and present it with your claim. This is a straightforward wind claim and the ACC clause should not apply.

Scenario 2: Mixed damage — wind damaged the structure, surge entered later through already-failed openings

This is the most contested and most common scenario. The key question is causation sequencing. If wind failed the roof and openings first, and water then entered through those openings, an argument exists that the water damage is a consequence of the covered wind loss — not an independent flood peril. A forensic engineer can document the failure sequence and support this argument. However, if surge also independently entered the property (different water stain heights, different debris patterns, different damage types at different elevations), the insurer will argue that surge contributed concurrently and invoke the ACC clause.

Scenario 3: Property is in a surge zone, both wind and surge damage are clearly present

This is the hardest scenario. When your property is in Zone A or AE, surge maps show inundation to 6+ feet, and the first floor shows both wind-driven rain damage at ceiling level and waterline marks at 4 feet, the insurer has a real basis for an ACC argument. Your goal is not to pretend surge didn't occur — it is to quantify and document which specific damage elements are attributable to wind only, and pursue coverage for that portion.

How to Document Against Concurrent Causation — Before and After the Storm

PRE-STORM DOCUMENTATION (do this before every season)
✓Photograph all four exterior elevations, close-up and wide, with timestamps — establishes pre-storm condition of every surface
✓Document existing waterline marks, stains, or prior moisture damage — prevents post-storm confusion about what was pre-existing
✓Know your FEMA flood zone designation and the storm surge advisory zone for your specific address
✓Identify the nearest NOAA tide gauge or DEM station — this will be critical for post-storm surge documentation
✓Obtain your insured value, hurricane deductible, and specific policy language for the flood exclusion and ACC clause
POST-STORM DOCUMENTATION (do immediately after the storm)
✓Photograph all damage before any cleanup — water intrusion patterns, debris location, structural failure direction
✓Document high-water marks with a measuring tape — the height tells you whether it was wind-driven rain (ceiling/upper walls) or surge (floor level rising)
✓Photograph any debris that indicates surge origin — marine debris, mud, vegetation from outside, fish
✓Request the NOAA storm surge inundation map for your county as soon as NOAA publishes it — typically within 48–72 hours post-landfall
✓Do not authorize emergency cleanup that obscures the water intrusion evidence — document fully before mitigation begins

What to Do When Your Claim Is Denied Under the ACC Clause

A denial is not a final answer. Florida property managers have multiple avenues to challenge a concurrent causation denial:

1. Demand the denial in writing. FL Stat 627.70131 requires insurers to communicate claim decisions in writing. The denial letter must reference the specific policy provision being invoked. Demand this if it was not provided, and read it carefully — ACC denials that do not properly match the policy language may be vulnerable.

2. Hire a forensic engineer. A licensed structural or civil engineer can prepare a causation analysis report that separates wind damage from flood damage. This report becomes the foundation of your supplemental claim or appraisal dispute. Engineers who specialize in hurricane damage — particularly in coastal counties like Lee, Collier, Charlotte, Sarasota, and Pinellas — understand how to document damage origin in ways that are defensible in disputes.

3. File a supplemental claim with separated damage documentation. If your engineer's report shows that $80,000 of damage is attributable to wind and $40,000 to surge, file a supplemental claim for the wind-caused portion with the engineering report attached. Even if the original claim was denied entirely under ACC, a properly documented supplemental claim for the segregable wind damage is harder to deny.

4. Invoke the appraisal clause. Most Florida property policies contain an appraisal clause that allows either party to demand an appraisal of the loss amount when causation is agreed but amount is disputed. The appraisal process is not the right tool when coverage is denied outright — but if the insurer acknowledges some wind damage and disputes the amount, appraisal can resolve that efficiently.

5. File a DFS complaint for free mediation. The Florida Department of Financial Services offers a free mediation program for disputed property insurance claims under $500,000. The insurer is required to participate. Many claims settle at mediation without litigation.

6. File a Civil Remedy Notice under FL Stat 624.155. If you believe the insurer acted in bad faith — denying a claim it knew was covered, failing to investigate properly, or unreasonably delaying — you can file a Civil Remedy Notice giving the insurer 90 days to cure the violation. This is the prerequisite step to a bad faith lawsuit and often motivates a settlement offer.

The Real Prevention: Separate Flood Coverage

The most reliable way to eliminate concurrent causation disputes is to eliminate the coverage gap that makes them possible. If your property has both a wind/landlord policy and a flood policy — NFIP or private — then both perils are covered and there is no basis for an ACC denial. Wind damage goes to the wind policy. Flood damage goes to the flood policy. The concurrent causation clause has nothing to exclude.

For Florida rental properties in Zone A, AE, VE, or X-shaded areas, the flood exposure is real enough that flood coverage should be treated as non-optional. NFIP premiums run $800–$2,500/year for residential properties at moderate risk. Private flood carriers — Neptune, Palomar, Wright Flood, and others — may offer better pricing, higher limits, or loss-of-rents coverage that NFIP does not provide.

The property managers who survived Ian, Helene, and Milton with intact finances were almost universally the ones who had both wind and flood coverage in force before landfall — and who had documentation systems that could separate the damage sources when both policies came into play.

Document and track hurricane damage claims in LossHQ

LossHQ's claim tracking system logs every damage event, photo, adjuster note, and payment by property — so you have a timestamped record ready for concurrent causation disputes before they happen.

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