Flood, Earthquake, and War: Why Some Risks Are Always Excluded

The Logic Behind Uninsurable Risks

Insurance works because risks are pooled. When your neighbor's kitchen catches fire, the premiums of thousands of policyholders who did not have a fire that year cover the loss. The math holds because house fires are statistically independent events — your misfortune does not cause your neighbor's.

Catastrophic perils break that model entirely. A major earthquake doesn't damage one building; it simultaneously damages tens of thousands across an entire region. A flood event tied to a hurricane can devastate an entire coastline in hours. A war can render entire cities uninhabitable overnight. When losses are highly correlated — meaning they happen to many insureds at exactly the same time — the pooling mechanism collapses. There is no offsetting premium base to draw from.

This is the fundamental actuarial reason these perils are excluded, and it's a reason grounded in math, not insurer indifference. Underwriters call this catastrophe accumulation risk: the danger that a single event wipes out reserves built up across an entire book of business.

Understanding this logic matters practically. It tells you why you cannot simply negotiate a flood rider onto a standard homeowners policy — the insurer isn't being difficult, the structure of conventional insurance just cannot absorb that exposure. It also clarifies why government programs and specialized reinsurance markets exist to cover these perils instead.

For a broader look at how exclusion clauses interact with policy structure, see named perils vs. open perils coverage— the type of policy form you carry determines whether exclusions work by omission or by explicit carve-out.

Flood: The Most Common and Costly Exclusion

Flood damage is the single most widespread uninsured risk in American property ownership. According to FEMA, just one inch of floodwater can cause more than $25,000 in damage to a home. Yet the standard Insurance Services Office (ISO) homeowners policy form explicitly excludes flood in language that leaves no room for interpretation.

The exclusion typically covers: surface water, waves, tidal water, overflow of any body of water, and water that backs up through sewers or drains caused by flooding. It does not matter whether the flood originated from a natural event or infrastructure failure — if the mechanism involves water entering from outside the structure due to these conditions, the standard policy will not respond.

The private market largely abandoned flood coverage after a series of catastrophic storms in the mid-twentieth century. The National Flood Insurance Program, administered by FEMA, was created in 1968 specifically to fill this void. Today, NFIP policies are available to homeowners, renters, and businesses in participating communities. A private flood insurance market has re-emerged in recent years, offering in some cases higher coverage limits and broader terms than NFIP.

For homeowners, the gap is frequently invisible until a claim is filed. Many owners in low-to-moderate flood zones assume a standard policy covers them, or mistake flood damage for storm damage (wind-driven rain through a broken window is typically covered; rising water from a storm surge is not). This distinction has cost property owners billions in uncovered losses.

The flood coverage gap explained goes into granular detail about exactly where standard policy protection ends and where flood coverage must begin.

For commercial properties, the exposure is often larger and the options more complex. Flood sublimits, waiting periods, and elevation certificates all factor into commercial flood underwriting in ways that residential policyholders rarely encounter. See what standard commercial property policies exclude for the business-specific implications.

Earthquake: A Separate Market, Not an Add-On

Earthquake exclusions are universal in standard property forms. The ISO CP 10 30 commercial property form and HO-3 homeowners form both exclude earth movement explicitly — and that language is broad enough to encompass not just earthquakes but landslides, sinkholes, and subsidence as well.

The concentration of risk is particularly severe for earthquake. The New Madrid Seismic Zone in the central U.S., the Cascadia Subduction Zone in the Pacific Northwest, and the San Andreas Fault in California each represent scenarios where a single event could generate insured losses in the hundreds of billions of dollars. The 1994 Northridge earthquake produced approximately $20 billion in insured losses — and that was a moderate event in a well-developed insurance market.

In California, the 1994 Northridge earthquake triggered such severe insurer losses that most carriers stopped writing earthquake coverage in the state. The California Earthquake Authority (CEA) was created in 1996 as a publicly managed, privately funded entity to restore market availability. Outside California, private earthquake insurance is available through admitted and surplus lines carriers, but take-up rates remain low — often below 15% even in high-risk zones.

Earthquake deductibles deserve particular attention. Unlike standard property deductibles, earthquake deductibles are typically expressed as a percentage of insured value — often 10% to 25%. On a $500,000 home, that's a $50,000 to $125,000 out-of-pocket exposure before the policy pays anything. Many property owners discover this only when they file a claim.

Business interruption triggered by earthquake damage is a separate and equally important exposure. Standard business interruption coverage attaches to direct physical loss from covered perils — and since earthquake is excluded from the underlying property form, business interruption from earthquake is also excluded unless the earthquake endorsement specifically extends to it.

Everything a standard dwelling policy does not cover provides a useful inventory of structural and property exclusions beyond just earthquake, for homeowners assessing their full exposure picture.

War: The Exclusion You Cannot Buy Around

The war exclusion is the most absolute of the three. It appears in virtually every property, liability, and specialty policy form, and unlike flood or earthquake, there is no conventional private market alternative for most policyholders.

Standard war exclusion language typically bars coverage for loss caused directly or indirectly by: declared or undeclared war, civil war, insurrection, rebellion, revolution, warlike acts by military forces, and governmental seizure or destruction of property for military purposes. Courts have generally interpreted war exclusions broadly, and policy language frequently extends to actions by sovereign powers whether or not a formal declaration of war exists.

“The war exclusion is not a technicality — it is a foundational boundary of the insurance contract. No insurer can price, reserve, or reinsure unlimited sovereign risk. The exclusion exists because the alternative is insolvency.”

— Robert Hartwig, Director, Risk and Uncertainty Management Center, University of South Carolina; former President of the Insurance Information Institute

The rationale is straightforward: war produces potentially unlimited, unquantifiable losses. No private insurer can reserve against a scenario where an entire country's infrastructure is destroyed. Even reinsurers — who cover insurers — exclude war from standard reinsurance treaties. The loss scenario is simply too open-ended.

What is available in specific contexts:

• TRIA (Terrorism Risk Insurance Act): Created after September 11, 2001, TRIA provides a federal backstop for certified acts of terrorism. This is distinct from the war exclusion — a terrorist attack may be covered under TRIA even if it would otherwise trigger war exclusion language, depending on whether the government certifies the event. Most commercial property policies include TRIA coverage.
• Political risk insurance: Available to multinational corporations and trade finance participants, covering losses from expropriation, political violence, and currency inconvertibility. This is a specialty product, not a standard commercial line.
• Marine war risk coverage: Ships and cargo have a separate war risk market that has existed for centuries. Lloyd's of London remains a primary market for this coverage.

For individual homeowners and small businesses, the war exclusion is effectively non-negotiable and non-circumventable. The practical implication: losses from civil unrest, rioting, or looting — which are different from war — may be covered under standard property policies, though this depends on specific policy language and jurisdiction.

Understanding how 'acts of God' function in exclusion clauses helps clarify how insurers categorize and distinguish between natural catastrophes and human-caused events in their policy language.

Reading Exclusions Before You Have a Claim

The declarations page of a policy shows what you have. The exclusions section — typically buried in the policy conditions — shows what you don't. Most policyholders read the first and never see the second until a claim is denied.

For homeowners and renters: the starting assumption should be that flood and earthquake are not covered. If you live anywhere near a coast, river floodplain, or geologically active region, investigate standalone coverage before your next renewal. FEMA's Flood Map Service Center provides official flood zone designations by address — this is the place to start, not your agent's general assurance that you're "probably fine."

For business owners: the exposure is typically larger, and the exclusion language more complex. Commercial property forms often include earth movement and water damage exclusions that are broader than residential forms. Business interruption coverage — which replaces lost revenue during a covered shutdown — is only as broad as the underlying property coverage. An earthquake that destroys your building and halts operations for six months produces exactly zero in business interruption recovery if earthquake isn't a covered peril.

Standard homeowners exclusions covers the full landscape of what typical policies omit, which extends well beyond the catastrophic perils discussed here.

The appropriate action after identifying a gap is not to assume the risk away — it's to quantify the exposure and decide deliberately whether to transfer it, retain it, or mitigate it. That is what informed risk management looks like in practice.

Your Options When Standard Coverage Falls Short

The exclusions are fixed. Your response to them is not. Here is a structured picture of available alternatives for each major catastrophic peril:

Flood

• NFIP policy: Available in participating communities; covers up to $250,000 for residential structures and $100,000 for contents. Separate policies for structure and contents. No business interruption.
• Private flood insurance: Can offer higher limits, shorter waiting periods, and broader terms. Increasingly available from admitted and surplus lines carriers. Recommended for high-value properties that exceed NFIP limits.
• Excess flood: Commercial insureds with significant property values can purchase excess flood coverage above NFIP or primary private limits.

Earthquake

• Earthquake endorsement: Some insurers offer endorsements to existing property policies in lower-risk states.
• Standalone earthquake policy: Required in most high-risk states. Evaluate deductible structure carefully — percentage deductibles are the norm.
• CEA policies (California): The California Earthquake Authority offers several plan tiers; coverage can be customized for dwelling, personal property, and loss of use.

War

• TRIA (commercial policyholders): Confirm your commercial policy includes terrorism coverage under the Terrorism Risk Insurance Act. This is separate from war but covers the most likely scenario of organized political violence in a domestic context.
• Political risk insurance: For businesses with international operations exposed to government action, expropriation, or regional conflict.

Umbrella policies extend liability limits beyond standard policy caps but do not override property exclusions — they will not cover flood or earthquake damage to structures, which is a common misunderstanding worth clarifying explicitly.