Anti-Concurrent Causation Clause Guide

Some property losses have more than one cause. An anti-concurrent causation (ACC) clause can exclude damage that a covered cause and an excluded cause produce together—even if the covered cause happened first or contributed substantially.

That does not mean an excluded cause automatically eliminates coverage for the entire claim. If wind damages the roof and floodwater separately damages the ground floor, the flood exclusion does not necessarily erase the wind damage. But if wind and flood combine to damage the same wall, an ACC clause may exclude that combined damage.

The analysis begins by identifying what caused each part of the damage. The policy language and the law of the state that governs the policy then determine the result.

The examples focus on common language found in commercial property policies, including ISO-style causes-of-loss forms. Policy editions and carrier-specific forms vary and should be reviewed individually.

What does an ACC clause say?

One common exclusion lead-in reads:

“We will not pay for loss or damage caused directly or indirectly by any of the following. Such loss or damage is excluded regardless of any other cause or event that contributes concurrently or in any sequence to the loss.”

In plain English, the exclusion may apply even when another cause also contributed. “Concurrently” means at the same time; “in any sequence” means the causes can happen one after another.

The lead-in does not necessarily apply to every exclusion in the policy. In many forms, exclusions are divided into groups, and the ACC wording introduces only one group. Other exclusions may have different causation language, exceptions, or ensuing-loss provisions. The endorsement schedule can also add or replace relevant wording.

Carrier-specific policies may use different formulations. Some place ACC wording in a general exclusions preamble. Others build it into an individual exclusion—for example, an earth-movement definition that applies “regardless of whether combined with water.” Review the complete exclusion, its lead-in, its definitions, and any exceptions before drawing a conclusion.

ACC, efficient proximate cause, and concurrent cause

Three related concepts are often discussed together, but they ask different questions:

• Efficient proximate cause asks which cause was the main cause that set the chain of events in motion.
• Concurrent cause considers damage produced by more than one cause, including whether the causes were independent and whether at least one was covered.
• ACC language states how a listed exclusion applies when another cause contributes at the same time or earlier or later in the sequence.

Courts do not apply these concepts uniformly. Some jurisdictions allow insurers and policyholders to contract around a default causation rule through clear ACC wording. Others restrict the extent to which policy language can displace an efficient-proximate-cause rule. Even within one state, the result may turn on whether the causes were independent, whether they damaged the same property, and how the exclusion was drafted.

How courts have applied ACC language

Snow load and deteriorated roof trusses

In Colorado Intergovernmental Risk Sharing Agency v. Northfield Insurance Co., 207 P.3d 839 (Colo. App. 2008), a jury attributed 90% of a roof collapse to snow weight and 10% to excluded conditions that included decay and deterioration. The Colorado Court of Appeals held that the ACC wording barred recovery because covered and excluded causes contributed to the collapse.

The Colorado Supreme Court later granted certiorari on whether that 90/10 allocation permitted partial recovery despite the ACC clause. The parties settled, and the appeal was dismissed before the court issued an opinion. The Court of Appeals decision therefore should not carry the weight of a final state-supreme-court ruling. Its useful point is narrower: when covered and excluded causes combine to produce the same damage, ACC wording can defeat an attempted percentage allocation.

That does not establish a universal rule that any trivial contribution—such as 1%—will defeat coverage in every jurisdiction or under every policy.

Wind, flood, and ordinance-compliance costs

Hurricane losses often involve distinct wind damage, distinct flood damage, and damage to which both perils contributed. Those categories should not be collapsed into a single number without examining the policy and the evidence.

In JAW The Pointe, L.L.C. v. Lexington Insurance Co., 460 S.W.3d 597 (Tex. 2015), the insurer paid the covered wind-damage amount but denied ordinance-compliance costs associated with demolishing and rebuilding an apartment complex. The city’s substantial-damage determination had relied on an estimate that combined covered wind and excluded flood damage. The Texas Supreme Court held that the ACC clause excluded the ordinance-compliance loss because the combined damage triggered enforcement of the ordinances.

The holding was tied to the loss being claimed and the causal record. It did not erase the separately identified wind damage, which the insurer had already paid.

Burst pipe followed by earth movement

In Lawrence v. State Farm Fire & Casualty Co., No. C24-4008-LTS-MAR (N.D. Iowa June 25, 2025), a burst pipe released more than 200,000 gallons of water. Evidence indicated that the water contributed to disintegration of soil beneath the foundation and subsequent settlement.

The policy excluded earth movement regardless of whether it combined with water and also contained ACC wording. The court granted summary judgment to the insurer, holding that the earth-movement exclusion applied even if the burst pipe initiated the sequence.

The District of Connecticut reached a similar result in Dalmac Realty LLC v. Scottsdale Insurance Co., No. 3:24-cv-00942 (D. Conn. Oct. 30, 2025). A broken water line preceded soil consolidation, settlement, and structural damage. The court held that the earth-movement exclusion and its ACC lead-in barred coverage for the claimed property damage.

These decisions illustrate why a covered plumbing event does not answer the coverage question by itself. The policy may separately address the resulting soil movement, settling, water, collapse, or ensuing loss.

Why jurisdiction matters

ACC enforceability and causation rules vary by state. The following examples illustrate the differences; they are not a complete fifty-state survey.

Washington

Washington applies the efficient-proximate-cause rule when two or more perils combine in sequence and a covered peril is the predominant cause. The Washington Supreme Court has said that the rule cannot be circumvented by exclusionary wording. See Key Tronic Corp. v. Aetna (CIGNA) Fire Underwriters Insurance Co., 124 Wn.2d 618, 881 P.2d 201 (1994). The analysis still requires identifying the efficient cause and reading the exclusions and exceptions as a whole.

California

California Insurance Code section 530 incorporates an efficient-proximate-cause framework: coverage generally turns on whether an insured peril was the proximate cause rather than merely a remote cause. California law does not permit an exclusion to defeat coverage simply by pointing to a remote excluded event when a covered peril was the efficient proximate cause.

That does not make all combination exclusions unenforceable. In Julian v. Hartford Underwriters Insurance Co., 35 Cal. 4th 747, 110 P.3d 903 (2005), the California Supreme Court enforced language excluding the specific peril of rain inducing a landslide. The court distinguished a valid definition of an excluded combined peril from wording used to reach a remote cause. The exact drafting and causal relationship therefore matter.

Texas

Texas courts generally enforce clear ACC language according to its terms. In JAW The Pointe, the Texas Supreme Court applied an ACC clause where covered wind and excluded flood damage combined to trigger ordinance enforcement. The court emphasized the policy wording and the evidence of what actually caused the claimed ordinance-compliance loss.

Florida

Florida recognizes a concurrent-cause doctrine in appropriate cases involving independent causes. In Jones v. Federated National Insurance Co., 235 So. 3d 936 (Fla. 4th DCA 2018), the court stated that its concurrent-cause framework applied when there were no applicable ACC provisions.

The decision should not be treated as a general rule overriding clear ACC wording. Florida analysis requires reviewing the particular clause and whether the asserted causes are independent.

Documenting and allocating damage

When multiple perils may be involved, the record should identify:

• which building components were damaged;
• the location and timing of each condition;
• the physical mechanism attributed to each cause;
• whether different causes produced separate damage or combined to produce the same damage;
• which conclusions are observations and which require engineering, meteorological, or other expert analysis; and
• how estimates allocate scope and cost among distinct categories of damage.

Allocation does not guarantee coverage. It gives the parties, appraisers, experts, and—if necessary—a court a clearer record on which to apply the policy. A blended estimate or loss narrative can make it difficult to determine whether claimed costs arise from covered damage, excluded damage, or a combination of both.

FAQ

Does an ACC clause exclude every loss involving more than one cause?

No. The clause applies only through the exclusions and wording that invoke it. Separate covered damage may remain covered even when another part of the loss is excluded. The evidence must show whether the causes produced distinct damage or combined to produce the same damage.

Does a small excluded contribution always eliminate coverage?

No universal percentage rule applies. The result depends on the clause, the causal record, and governing law. A court may enforce clear ACC wording against a mixed-cause loss, while another jurisdiction may limit the clause through an efficient-proximate-cause rule or statute.

Can an ensuing-loss exception restore coverage despite ACC wording?

Sometimes. The exception and the exclusion must be read together. An exception may preserve separate resulting damage without covering the excluded cause itself, but another exclusion or causation rule may still apply.

Why does allocation matter if the policy has an ACC clause?

Because an ACC clause does not necessarily erase damage caused independently by a covered peril. Component-level photographs, measurements, expert analysis, and estimates can show which damage is separate and which damage resulted from combined causes.

For Policyholder Representatives

ACC analysis should begin before a claim theory is fixed in correspondence, estimates, or expert assignments. The objective is an accurate, supportable account of the loss—not wording designed to avoid an exclusion.

Claim Intake Checklist for Policyholder Representatives

Run this checklist during claim intake, before the claim narrative, estimate structure, or expert assignment fixes a theory of causation.

When communicating about a multi-cause loss, describe observed facts precisely and avoid assigning causation beyond the available evidence. If later investigation changes the causal analysis, update the record rather than trying to preserve an early characterization.

ACC and Frontera

ACC wording is easy to miss when a review focuses only on the declarations or a list of excluded perils. Frontera’s Coverage Analysis can help locate relevant exclusions, conditions, and endorsements and link the findings to source policy pages for verification.

When causation disputes also produce competing scopes or estimates, Frontera’s Estimating tools can organize site documentation and compare scope, pricing, and quantity differences. The professional reviewing the claim remains responsible for confirming the policy language, evidence, and applicable law.

References

• Colorado Intergovernmental Risk Sharing Agency v. Northfield Insurance Co., 207 P.3d 839 (Colo. App. 2008), cert. granted, No. 08SC907, 2009 WL 1485804 (Colo. May 26, 2009), appeal dismissed after settlement
• JAW The Pointe, L.L.C. v. Lexington Insurance Co., 460 S.W.3d 597 (Tex. 2015)
• Lawrence v. State Farm Fire & Casualty Co., No. C24-4008-LTS-MAR (N.D. Iowa June 25, 2025)
• Dalmac Realty LLC v. Scottsdale Insurance Co., No. 3:24-cv-00942 (D. Conn. Oct. 30, 2025)
• Key Tronic Corp. v. Aetna (CIGNA) Fire Underwriters Insurance Co., 124 Wn.2d 618, 881 P.2d 201 (1994)
• California Insurance Code § 530
• Julian v. Hartford Underwriters Insurance Co., 35 Cal. 4th 747, 110 P.3d 903 (2005)
• Jones v. Federated National Insurance Co., 235 So. 3d 936 (Fla. 4th DCA 2018)
• Sebo v. American Home Assurance Co., 208 So. 3d 694 (Fla. 2016)

This article is for educational purposes and does not constitute legal advice. Policy language and governing law vary. Consult qualified coverage counsel regarding a specific claim or dispute.