Anti-concurrent causation is a short paragraph in a property policy that can decide a very large claim. It appears in the exclusions section, it is easy to skim past, and after a hurricane or a major storm it becomes the most consequential sentence in the document.
What the clause says
The wording varies, but the standard form reads close to this:
"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." Plain English: if an excluded cause played any part in producing the damage, the entire loss is excluded — even if a covered cause also contributed, and even if the covered cause did most of the work.
Read that second sentence again, because it is doing all the work. Without it, the ordinary rule in many states would apportion the loss between covered and excluded causes, or apply the dominant cause. The clause is written specifically to prevent that.
The scenario it was built for
The textbook case is a hurricane. Wind is covered under most homeowners policies. Flood and storm surge are excluded and require a separate policy, typically through the NFIP.
A house is damaged during a hurricane. Wind removed part of the roof; storm surge flooded the ground floor. Both happened within hours. With an anti-concurrent causation clause, the insurer may take the position that because an excluded cause — flood — contributed to the loss, the exclusion applies to the whole thing.
Whether that position holds is exactly what has been litigated repeatedly, and the answers differ by state.
Where else it appears
Hurricanes are the famous example, but the clause is not limited to them.
- Earth movement. A landslide after heavy rain. Rain damage may be covered; earth movement is generally excluded.
- Water damage combined with a maintenance issue. A sudden pipe failure in a wall where the insurer also identifies long-term seepage.
- Faulty workmanship. A storm damages a structure that was defectively built. Storm damage is covered; faulty construction is excluded.
- Ordinance or law. Damage occurs, and rebuilding to current code costs more than restoring what was there.
Why states treat it differently
This is the part that matters most and the part most often left out.
Anti-concurrent causation clauses are not enforced uniformly across the United States. Some states enforce them as written, on the reasoning that insurance policies are contracts and the parties agreed to the language. Other states apply the efficient proximate cause doctrine, under which the dominant cause that set the chain of events in motion determines coverage — and in some of those states the doctrine cannot be contracted around at all. A number of states have addressed the question by statute or by regulation rather than only through case law.
The practical consequence: the same facts, the same policy wording, and two different states can produce two different results. Anyone telling you what your clause means without knowing your state is guessing.
If a denial cites anti-concurrent causation and the amount at stake is significant, this is a category where consulting an attorney licensed in your state is worth serious consideration. The question is not really about the facts of your loss — it is about how your state's courts treat this specific clause.
How to find it in your own policy
Open the policy and go to the exclusions section, usually headed "Exclusions" or "Losses We Do Not Cover." The clause typically sits at the top, before the numbered list of excluded perils, as an introductory paragraph.
Search for these phrases: "concurrently or in any sequence", "directly or indirectly", "regardless of any other cause". If any of them appear before your exclusions list, your policy contains the clause.
Then read the exclusions that follow, because the clause only bites when one of them is implicated.
What can be examined when it is invoked
Several things, and none of them is a guarantee.
- Whether the excluded cause actually contributed. The insurer has to connect it to the damage. An engineering report saying flood water reached a certain height is a factual assertion that can be examined against evidence such as water lines, debris patterns, and timing.
- Whether the damage is separable. A roof torn off by wind before any water arrived is arguably a distinct loss from ground-floor flooding. Separating them is heavily fact-dependent and usually requires expert documentation.
- How your state treats the clause. The legal question, and the one that most often determines the outcome.
- Whether an ensuing loss provision applies. Some exclusions are followed by language covering damage that results from the excluded event, which can restore coverage for part of the claim.
What this means before a loss
The clause is one of the strongest practical arguments for understanding what your policy does not cover before you need it.
If you live where flooding is possible, a separate flood policy removes the ambiguity: flood damage is covered under the flood policy regardless of what the homeowners policy says about concurrent causes. The same logic applies to earthquake coverage where earth movement is a realistic risk.
This is not a recommendation to buy anything — we do not sell insurance and we receive nothing if you do. It is an observation about where anti-concurrent causation disputes come from: they arise almost entirely in the gap between two policies.
What we are not saying
We are not saying the clause is unenforceable, because in many states it plainly is enforceable. We are not saying your denial is wrong. And we are not telling you what your state's courts would do with your facts, because that requires a licensed attorney who has read your policy and your file.
What we are saying is that this clause is often the entire basis for a large denial, that its effect varies by state more than almost any other provision, and that a denial citing it deserves more scrutiny than most.
Where to verify this yourself
- Your policy — the exclusions preamble, and any ensuing loss language.
- Your state Department of Insurance — whether your state has addressed these clauses by statute or regulation.
- An attorney licensed in your state — how your courts apply efficient proximate cause. State bar referral services can help you find one.
- FEMA and the NFIP — what flood coverage is and how it differs from wind coverage.
How the clause changes the arithmetic
Without an anti-concurrent causation clause, a loss with two causes is generally handled in one of two ways depending on the state: the damage is apportioned between them, or the dominant cause determines coverage.
The clause overrides both.
The two doctrines, in plain terms
Efficient proximate cause Coverage is determined by the dominant cause that set the chain of events in motion. If that cause is covered, the resulting loss is covered even where an excluded peril appears later in the chain.
Concurrent causation Where two independent causes contribute and one is covered, coverage attaches. Anti-concurrent causation language is written specifically to displace this.
Freedom of contract The reasoning courts use when enforcing the clause as written: the parties agreed to the language, and a policy is a contract.
States divide roughly along these lines. Some enforce the clause as written, on freedom of contract reasoning. Others apply efficient proximate cause, and in some of those it is treated as a matter of public policy that cannot be contracted around. A number have addressed the question by statute or regulation rather than through case law alone.
We are deliberately not printing a state-by-state list. Case law in this area develops, and a list that is wrong on your state would be worse than no list — particularly on a question where the difference is a whole claim.
Where these disputes actually arise
| Scenario | Covered element | Excluded element |
|---|---|---|
| Hurricane | Wind | Flood, storm surge |
| Landslide after heavy rain | Rain damage | Earth movement |
| Pipe failure in a wall | Sudden discharge | Long-term seepage |
| Storm damage to defective construction | Windstorm | Faulty workmanship |
| Roof collapse under snow | Weight of ice and snow | Pre-existing structural defect |
| Sewer backup during flooding | Water backup, if endorsed | Flood |
Notice the pattern: almost every one pairs a weather event with a condition of the property or with a second water source. That is not coincidence. The clause does its work at exactly the boundary where two policies meet, or where a property's condition meets an event.
What can be examined, in practice
Whether the excluded cause actually contributed
This is factual and it is checkable. If flood is asserted, the assertion carries physical implications — a water line at a given height, debris patterns, silt deposits, damage to items at particular elevations.
Where the interior damage sits above any established water line, or where the sequence shows the roof opened before water arrived, the factual basis for asserting flood contribution to that damage weakens. Establishing this generally requires an engineer or a qualified adjuster, not an argument.
Whether the damage is separable
Even in states enforcing the clause, the analysis applies to a loss produced by combined causes. Damage that is genuinely attributable to one cause alone is a different question.
A roof torn off by wind at 2 a.m., with ground-floor flooding at 6 a.m., is arguably two losses rather than one. Separating them is fact-intensive and requires documentation of sequence and elevation — which is why timestamps on photographs, weather records, and any contemporaneous account matter so much in these claims.
Whether an ensuing loss provision restores part of it
Many exclusions are followed by language covering damage that results from the excluded event. Read the whole provision. The interaction between an anti-concurrent causation preamble and an ensuing loss carve-back is genuinely technical, and it is one of the clearest situations in which a policyholder benefits from professional advice.
What to gather when this clause is cited
Documentation that addresses the argument
- Photographs and video with timestamps, taken before any cleanup
- Any evidence of sequence — when the roof opened, when water arrived
- Water line evidence: height, silt, staining on walls and contents
- Damage inventories by elevation, distinguishing what sat above any water line
- National Weather Service records for the date and location
- An engineering assessment addressing causation directly
- The full text of the exclusions section, including the preamble and any ensuing loss language
What this means when buying coverage
The clause bites in the gap between two policies. That observation points to the only reliable way to avoid the dispute entirely: not having a gap.
Where flooding is a realistic risk, a separate flood policy means flood damage is covered under the flood policy regardless of what the homeowners policy says about concurrent causes. The same logic applies to earthquake coverage where earth movement is plausible.
We do not sell insurance and receive nothing if you buy any. This is an observation about where these disputes come from, and it is the single most useful thing to know before a storm rather than after.
When to get advice
Most of what this site covers can be worked through yourself. This is one of the exceptions.
A denial resting on anti-concurrent causation turns on a question of state law that varies more than almost any other provision, and the amounts involved are typically large because the clause is invoked on major losses. If your denial cites it and the sum is significant, an attorney licensed in your state is the person who can tell you what your courts do with this language. State bar referral services can help you find one.
This is general education, not advice. Insurance law and claim rules vary by state and change over time. Nothing here is legal, financial, or insurance advice for your situation, and reading it does not create any professional relationship. For your specific case, consult a licensed professional in your state or contact your state Department of Insurance.