A wildfire takes the garage. A hurricane peels off half the roof. A flash flood ruins the inventory in your storefront. Most taxpayers assume they have to wait until next April to write the loss off — and many wait an entire year and a half before any cash actually shows up. The federal tax code offers a workaround almost nobody talks about: an election that lets you claim the casualty loss on a return you've already filed, generating a refund within weeks instead of next tax season.
That tool is Section 165(i) of the Internal Revenue Code, and it can be the difference between waiting until April 2027 for relief and depositing IRS money in your account before the debris is even cleared. With FEMA tracking more than 100 disaster declarations a year and 2025 producing major declarations across California wildfires, Texas flooding, Missouri tornadoes, Washington landslides, and dozens of other events, the election matters for a lot more taxpayers than the people who realize it.
This guide walks through how the election works, the deadlines you cannot miss, the calculation rules for personal and business property, and the safe harbors that let you skip an expensive appraisal.
What Section 165(i) Actually Does
Casualty losses normally flow through the tax return for the year the loss occurs. If your home burns down in October 2026, the deduction shows up on the 2026 return you file in 2027.
Section 165(i) breaks that timing rule for one specific category: losses "attributable to a federally declared disaster" occurring in a "disaster area." For those losses — and only those losses — you can elect to deduct them on the return for the year immediately before the disaster year.
In practical terms, if a federally declared disaster hits your property in 2026, you can attach a 2026 Form 4684 to an amended 2025 return (Form 1040-X), claim the loss against income you've already reported, and the IRS issues a refund check based on the recalculated 2025 liability. You do not have to wait twelve to eighteen months to monetize the loss.
The election was designed for exactly this cash-flow problem. Insurance pays slowly. Federal Emergency Management Agency (FEMA) individual assistance is capped and slow. Rebuilding starts immediately. Pulling the tax savings forward by a year is one of the few sources of fast, sizable liquidity for a disaster-hit household.
Who Qualifies
Three conditions must all be met:
- The loss must be attributable to a federally declared disaster. That means the President of the United States declared the event a major disaster or emergency under the Stafford Act. Each declaration carries a FEMA-assigned DR (major disaster) or EM (emergency) number, and the property must sit in a county listed in the declaration.
- The loss must be a true casualty loss — sudden, unexpected, or unusual damage to property. Gradual deterioration, normal wear, and progressive flooding from a leaky pipe do not qualify.
- The taxpayer must actually own the property or be contractually liable for it. Renters can claim losses on their personal belongings inside a damaged rental, but cannot claim damage to the structure itself.
Both individuals and entities can use the election. Sole proprietors, single-member LLCs, partnerships, S corporations, and C corporations all have access — though the calculation mechanics differ between personal-use and business property.
If a particular disaster also qualifies as a qualified disaster under specific federal legislation (most major events between 2020 and September 2, 2025 qualify), the loss enjoys enhanced rules described below.
The Hard Deadline You Cannot Miss
Here is where most taxpayers stumble. The 165(i) election is not on the same clock as a normal amended return.
You must make the election no later than six months after the regular due date (without extensions) of the original return for the disaster year. For a 2025 disaster suffered by a calendar-year individual, the disaster year return is due April 15, 2026 (without extensions), so the election deadline is October 15, 2026. For a 2026 disaster, the election deadline is October 15, 2027.
Importantly, this is the deadline to make the election, not to amend the prior year. The amended prior-year return can still be filed under the normal three-year statute, but the choice itself must be elected within the six-month window.
You also have a 90-day window to revoke the election after making it. Some taxpayers run the numbers and discover the disaster year's marginal rate is higher than the prior year's; in that case, revoking gets you back to the default treatment. After 90 days the choice is locked in unless the IRS grants permission to change it, which is rare.
Mark these dates in a calendar the day the disaster occurs. The deadline does not move because you were busy rebuilding.
How to Make the Election
Mechanically, the election is straightforward:
- Complete Form 4684 for the disaster year, Section D. This is the section dedicated to the prior-year election. Enter the FEMA DR or EM number in the space above line 1.
- Attach the Form 4684 to either an original or amended prior-year return. If the prior year is already filed, file Form 1040-X. Businesses use the appropriate amended return — 1120-X for C corporations, amended 1120-S for S corporations, amended 1065 for partnerships.
- Include a written statement declaring the election. The statement must identify the disaster, the date of the loss, the address or description of the affected property, and a clear declaration that the taxpayer elects under Section 165(i) to claim the loss in the preceding year.
- Recalculate the prior-year tax with the casualty deduction included and request the resulting refund.
The IRS expedites disaster-related refunds in most cases — writing "Disaster" and the FEMA declaration number at the top of the return helps route it to a designated processing team.
Calculating the Loss: Personal-Use Property
For property that is not used in a trade or business or held for investment, the casualty loss calculation runs through a specific formula.
Step 1: Determine the decrease in fair market value. This is the FMV immediately before the casualty minus the FMV immediately after. For total destruction, the "before" FMV is the relevant number; for partial damage, both numbers matter.
Step 2: Compare to adjusted basis. The deductible loss for personal-use property is the smaller of the decrease in FMV or the adjusted basis in the property.
Step 3: Subtract insurance and other reimbursements. Reduce the loss by any amount received — or reasonably expected to be received — from insurance, FEMA, GoFundMe campaigns, or other sources. If you fail to file a timely insurance claim on a covered loss, the IRS treats the unclaimed coverage as if you received it.
Step 4: Apply the $100 per-event floor. Each separate casualty event triggers a $100 reduction. A single hurricane damaging both your house and your car is one event with one $100 floor.
Step 5: Apply the 10% AGI threshold. Standard casualty losses are deductible only to the extent the total exceeds 10% of adjusted gross income for the year of deduction (the prior year, if you elect).
For losses that qualify as qualified disaster losses under specific federal legislation, the rules are far more generous: the $100 floor becomes a $500 floor per event, the 10% AGI threshold disappears entirely, and the loss is deductible without itemizing — it can be added to the standard deduction.
Calculating the Loss: Business Property
Business and income-producing property follows a different and generally more taxpayer-friendly path.
For completely destroyed business property, the loss equals adjusted basis minus salvage value minus insurance reimbursement, regardless of FMV. This means a fully depreciated piece of equipment generates no loss even if its market value was significant — there is nothing left in basis to write off.
For partially destroyed business property, the loss is the smaller of the decrease in FMV or the adjusted basis, less reimbursements — similar to the personal-use formula.
The critical difference: no $100 floor and no AGI threshold apply. Business casualty losses flow through the return in full.
For pass-through entities, the loss passes to owners on their K-1s. The 165(i) election can be made at the entity level, accelerating the loss onto the prior-year K-1 — though all partners or shareholders need to coordinate, because the election affects everyone's prior-year return.
Inventory losses do not go on Form 4684. They are absorbed through cost of goods sold, with any insurance recovery treated as ordinary income. A clothing boutique flooded out should not double-count inventory losses by also putting them on the casualty schedule.
Safe Harbors That Save the Appraisal Bill
Pinning down the "decrease in fair market value" usually requires an appraisal — expensive, slow, and often hard to commission while contractors are booked solid. Revenue Procedure 2018-08 carves out seven safe harbors that let taxpayers skip the formal appraisal entirely. If you follow the safe harbor correctly, the IRS will not challenge the FMV determination.
For personal-use residential real property, four safe harbors apply:
- Estimated repair cost method (limit $20,000): Use the lesser of two estimates prepared by separate, independent licensed contractors. The estimates must detail line-item costs to restore the property to its pre-casualty condition.
- De minimis method (limit $5,000): The homeowner can make a good-faith estimate of the repair cost based on receipts, photos, and observations. No contractor required.
- Insurance safe harbor: Use the loss estimate the insurance company put together. This is the easiest method when coverage exists.
- Contractor safe harbor (federally declared disasters only): Use a binding contract with a licensed contractor for restoration work, signed within a reasonable time after the disaster.
- Disaster loan appraisal (federally declared disasters only): Use the appraisal supplied with a federal disaster loan application — SBA loans, for instance, come with an inspection.
For personal belongings (furniture, clothing, electronics, kitchenware):
- De minimis method (limit $5,000): Good-faith estimates of decline in value, item by item.
- Replacement cost safe harbor (federally declared disasters only): Determine the cost to replace each item new today, then reduce by 10% for each year of ownership, capped at a 90% reduction. For unique or older items, this often produces a more favorable answer than fair market value.
Document the method used. Photos of damage, receipts, contractor estimates, and item-by-item belonging schedules belong in a single file labeled with the disaster year and FEMA number.
When the Election Actually Helps — and When It Doesn't
The 165(i) election is not automatically beneficial. The right answer turns on comparing marginal tax rates between the two years and the cash-flow value of an earlier refund.
The election helps when:
- The prior year had higher income and therefore higher marginal rates. A loss deducted in a 32% bracket year saves more tax than the same loss in a 22% bracket year.
- The prior year had sufficient income to absorb a large deduction without wasting it. Casualty losses cannot create negative tax — though excess business losses can flow into a net operating loss.
- The taxpayer needs cash now to rebuild and cannot wait until the following filing season.
- The taxpayer has already filed the prior-year return, making an amended-return refund the fastest path.
The election may not help when:
- The disaster year will have substantially higher income than the prior year — a small business that surges in the second half of the year despite damage, for example.
- The prior year had low or zero income, so the deduction would be partially wasted.
- The 10% AGI threshold consumes more of the loss in the prior year than it would in the disaster year (e.g., the disaster year will produce lower AGI).
- The loss is a qualified disaster loss and an itemized prior-year return would lose value compared to a standard deduction plus qualified disaster loss in the disaster year.
A simple two-column comparison — disaster-year tax with the loss versus prior-year tax with the loss — answers the question in fifteen minutes for most filers.
Coordinating With Insurance and Reimbursements
A subtle trap snares taxpayers who claim a 165(i) deduction before insurance pays out. The casualty loss must be reduced by reimbursements reasonably expected, not just amounts already received. If a homeowner deducts a $200,000 loss in year one and then receives a $150,000 insurance check in year two, the result is not a recalculation of the prior-year return — it is a reimbursement income inclusion on the year-two return, reported on Form 4684.
The cleanest sequence:
- File the insurance claim promptly.
- Estimate the expected reimbursement conservatively when making the election.
- Document the estimate in the casualty workpapers.
- Report any over- or under-recovery in the year payment is finalized.
If insurance fully reimburses the loss, there is no casualty deduction — but if the reimbursement triggers a gain (proceeds exceed adjusted basis), Section 1033 separately allows deferring that gain by reinvesting in similar replacement property within two years (four years for a principal residence in a federally declared disaster).
Recordkeeping the IRS Expects
Casualty-loss returns are audited at a higher rate than typical individual returns. Bulletproof documentation includes:
- Proof of ownership (deed, title, lease for personal property of renters)
- Pre-casualty condition evidence — photos, prior appraisals, purchase receipts, insurance schedules
- Post-casualty condition evidence — photos, contractor estimates, FEMA inspection reports
- The cause and date of the casualty — news articles, the FEMA declaration number, weather reports
- Insurance claim filings and payments — including the policy declarations page showing coverage
- All contractor estimates and invoices used in safe-harbor valuations
- A loss schedule — item-by-item for personal belongings, basis-tracking for real property and business assets
Keep these for at least seven years after the deduction. Section 165 losses occasionally surface in later disputes over basis when property is sold.
Coordinating With Other Disaster Relief
The 165(i) election sits in a broader tax-relief landscape:
- Filing and payment extensions: The IRS automatically postpones returns and payments for taxpayers in covered counties — the 2025 California wildfire victims, for example, received extensions to October 15, 2025 for various 2024 filings.
- Qualified disaster relief payments received from FEMA, state agencies, or employers for personal expenses, funeral costs, or home repairs are excluded from gross income under Section 139. Do not include these in the income calculation.
- Retirement account hardship distributions related to a qualified disaster are exempt from the 10% early withdrawal penalty and can be repaid over three years.
- Net operating loss carryback generally is not available for individuals after 2017, but excess business losses that include casualty losses can carry forward.
Stack the right combination. A small-business taxpayer with a 2026 disaster might extend the 2025 filing, claim the casualty under 165(i) on an amended 2025 return for fast cash, exclude FEMA grants from income, and tap a hardship retirement distribution without penalty — all from the same event.
Common Mistakes That Trigger IRS Notices
Several patterns reliably draw IRS scrutiny on casualty-loss returns:
- Skipping the $100/$500 floor on personal-use losses.
- Forgetting the 10% AGI reduction on non-qualified disaster losses.
- Claiming sentimental value for damaged or destroyed items — only economic loss counts.
- Deducting personal protection costs like sandbags or evacuation expenses — these are not casualty losses.
- Missing the six-month election deadline and trying to amend later.
- Failing to file a timely insurance claim on covered property — the IRS treats the unclaimed coverage as a constructive reimbursement.
- Inventory casualty losses on Form 4684 instead of through cost of goods sold.
- Mixing up the disaster year and election year on Form 4684 Section D.
- No FEMA declaration number on the form, which slows or stops processing.
A clean return with a clear FEMA number, documented safe-harbor valuation, and a signed election statement processes far faster than one missing any of these elements.
Special Considerations for Small Businesses
A small business hit by a federally declared disaster has three layered choices:
- Section 165(i) election to accelerate the casualty deduction into the prior year.
- Filing extensions that push the disaster-year return to a postponed date.
- Net operating loss carryforward if the loss creates negative taxable income.
For a sole proprietor, the 165(i) election generates a refund from the prior year's Schedule C income tax and self-employment tax. For an S corporation, the loss flows to shareholder K-1s; if shareholders agree, all of them amend prior-year returns. For a partnership, the same coordination problem exists — partners can elect together to use the prior-year mechanism.
Cash-basis businesses should also remember that an accrual to a damaged customer or supplier may produce its own loss, and that contract penalties for non-delivery during a disaster can sometimes be deducted in the year imposed.
The 165(i) election is most powerful when paired with disciplined bookkeeping. Reconstructing pre-disaster inventory, depreciation schedules, and asset basis from scorched paper records is a nightmare; a clean general ledger turns the process into an afternoon. This is also where plain-text accounting earns its keep — disaster-resilient records do not live in one filing cabinet.
A Note on State Tax Treatment
State income tax rules generally follow the federal casualty loss treatment, but with notable exceptions. California, New York, and a handful of others have their own disaster-loss provisions that may allow looser rules — including federal disasters that were not declared major and prior-year elections on state returns that mirror Section 165(i). Check the state's franchise tax board guidance after a major event.
Some states also offer their own property tax abatement for damaged or destroyed property, which is separate from the income tax casualty loss and worth pursuing in parallel.
Keep Your Finances Audit-Ready Before the Next Storm
The taxpayers who fare best after a disaster are not the ones with the most insurance — they are the ones whose financial records survive intact. Photographs, basis schedules, asset registers, and clean prior-year returns determine whether a 165(i) election takes a day or a month to prepare, and whether the IRS waves it through or audits it.
Beancount.io provides plain-text accounting that lives in version-controlled files instead of a proprietary database — your books and supporting schedules are as portable as a text file and as resilient as your backup strategy. For freelancers, small businesses, and households tracking significant property basis, that durability is a quiet form of disaster preparedness. Get started for free and see why developers, accountants, and finance teams choose transparent, AI-ready accounting that does not lock them into a vendor or a single device.