Anti-Concurrent Causation (ACC)

What it means

Anti-Concurrent Causation (ACC) is a contract provision found in most Florida property insurance policies that governs what happens when two or more perils act together to cause a single loss. When a covered peril and an excluded peril combine, or occur in sequence, to produce the same damage, an ACC clause allows the insurer to deny the entire loss, not just the portion attributable to the excluded peril. The clause typically appears in the policy's exclusions section and uses language stating that certain losses are not covered regardless of any other cause or event contributing concurrently or in any sequence to the loss.

The clause exists because insurers price and reserve for specific, defined risks. Flood, storm surge, and rising water are treated as a separate risk category that standard homeowners policies do not cover. Flood coverage in the United States is generally provided through the National Flood Insurance Program (NFIP), administered by the Federal Emergency Management Agency (FEMA), and must be purchased as a separate policy. Because a single hurricane can produce both wind damage (a covered peril) and flood or storm-surge damage (an excluded peril) to the same structure, insurers use ACC language to draw a firm line: if an excluded cause is part of the causal chain, the exclusion controls the outcome, even where a covered cause also contributed.

In practice, ACC turns causation into the central battleground of a Florida storm claim. If a roof is torn open by wind and the interior is then soaked by wind-driven rain, the loss is generally within coverage. But if the same home is also inundated by storm surge, the carrier may invoke the ACC clause to argue that flood, an excluded peril acting concurrently, defeats coverage for the combined damage. The homeowner's recovery can then depend entirely on proving which damage the wind caused before any water intrusion, and separating it cleanly from anything the flood touched.

It is important to understand what ACC is not. It is a policy term, not a Florida statute, and its enforceability and reach depend on the exact wording of the policy and how a court reads it. Florida is not a pure concurrent-causation state by statute, so the specific ACC language in the contract carries real weight. This makes reading the actual policy, rather than relying on the adjuster's summary, essential before conceding that a loss is excluded.

In practice

On a real Florida hurricane claim, ACC most often surfaces after a coastal or low-lying home takes both wind and water damage. The carrier's field adjuster inspects, notes evidence of standing water or a surge line, and the file is routed toward an ACC-based denial or a sharply reduced payment. The burden then shifts to the policyholder to show what the wind did independently: roof coverings lifted, openings created, and interior damage that occurred from wind and wind-driven rain before any flooding entered the structure. Photographs, weather and tide data, and a methodical room-by-room damage allocation are what turn a blanket denial into a defensible wind claim.

A common pitfall is treating one storm as one claim. Wind is covered by the homeowners policy; flood is covered only by a separate NFIP policy. Homeowners who carry both should generally open both claims, because allocating damage between the two carriers is often the only path to a full recovery and prevents the wind insurer from using flood as a total ACC defense. Carrier tactics to watch for include over-attributing interior damage to surge, leaning on a single surge waterline photo to exclude damage well above it, and issuing early low estimates before the full extent of wind damage is documented.

Because ACC turns on the precise policy wording and on causation evidence, timing and documentation matter. Florida law also imposes a presuit step: under Florida Statute 627.70152, a policyholder must serve a written notice of intent to initiate litigation on the Department of Financial Services at least 10 business days before filing suit under a property policy, and the insurer must respond in writing within 10 business days after receiving the notice. Preserving evidence early, before repairs erase the wind-versus-water picture, keeps that later leverage intact.

Related guide: Hurricane Damage Claims in South Florida