Glossary

Concurrent causation

How a property loss is treated when a covered peril and an excluded peril combine to cause it, which court rules and policy wording answer differently.

Also called: concurrent causes, concurrent cause doctrine, efficient proximate cause, anti-concurrent causation

Concurrent causation comes up when a covered peril and an excluded peril both contribute to one loss: wind-driven rain and floodwater in the same building, or a hurricane's wind and storm surge on the same roof. Whether the policy pays depends on the rule applied.

Many states follow the efficient proximate cause doctrine: if the predominant cause is covered, the loss is covered even though an excluded peril played a part. California's Supreme Court set that out in Garvey v. State Farm, 48 Cal.3d 395 (1989). Other states ask different questions, and outcomes vary.

Insurers answered with anti-concurrent causation wording. The ISO special causes of loss form (CP 10 30) opens its exclusions with "regardless of any other cause or event that contributes concurrently or in any sequence to the loss," so an excluded peril such as flood or earth movement defeats the claim even when a covered peril also contributed. Courts usually enforce that language when it is clear, as the Texas Supreme Court did in JAW The Pointe v. Lexington, 460 S.W.3d 597 (2015). A few states limit its enforcement, so the same loss can come out differently across state lines.

After a storm, document which peril did what and in what order. anti-concurrent causation clauses: when one excluded cause sinks a claim explains the clause in depth, causes of loss form shows where it sits in the policy, and exclusion covers how exclusions are read.

Last reviewed October 10, 2026

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Related terms

Causes of loss form The part of a commercial property policy that lists which perils are covered, offered in basic, broad and special versions of increasing breadth. Special form (open perils) A property causes-of-loss form covering direct physical loss from any cause not specifically excluded or limited, rather than only the perils it lists. Exclusion A policy provision that removes coverage for specified perils, property, people or types of loss that the insuring agreement would otherwise include. Named perils Property coverage that pays only for losses caused by perils the policy lists, such as fire, lightning and windstorm; an unlisted cause is not covered.

Related guides

Anti-concurrent causation clauses: when one excluded cause sinks a claim How the lead-in to the ISO special form's big exclusions works, how California and Texas courts treat it, and what to do when wind and water hit one building. Filing business insurance claims after a hurricane or wildfire How to protect property, report the loss, sort wind from flood and smoke from fire, claim business income and work the clocks after a hurricane or wildfire. Basic, broad and special causes of loss forms: what each covers ISO's three causes of loss forms decide which perils your property policy pays for. Compare CP 10 10, CP 10 20 and CP 10 30 and see where claims diverge. Commercial property exclusions: what the standard policy won't pay The ISO special form covers direct physical loss unless excluded. The exclusions that fail claims, how the three tiers read, and where each gap is bought back.