Casualty loss deduction 2026 OBBBA state disasters

Homeowners have long had a narrow path to casualty loss relief. Before OBBBA, a disaster had to reach federal disaster status before families and Individuals could even begin the deduction calculation. In 2026, that changed. OBBBA Sec. 70109 expands the deduction to state-declared disasters, making the rule much more practical for real-life events where federal attention is limited.

If your home was damaged after a governor's declaration, this can be a meaningful deduction, but only if you document and compute it correctly. The biggest mistakes come from missing filing details, incomplete records, and weak value estimates. This guide shows what changed, what did not, and how to claim the deduction cleanly.

OBBBA Section 70109 state disaster deduction rules

The pre-OBBBA rule is simple: casualty losses for personal property were generally deductible only in cases of federally declared disasters. The federal standard derives from the Robert T. Stafford Disaster Relief and Emergency Assistance Act and the presidential major disaster declaration process. That rule excluded many events, even when damages were real and significant.

OBBBA Sec. 70109 added governor-declared state disasters to the list. That is the core policy change in plain terms. A state declaration now extends eligibility for this same casualty deduction framework. It does not create a new tax for me, and it does not remove the old limitations. It just widens access.

The deduction is still claimed for personal losses caused by sudden, unexpected, or unusual events. Think of fire, flood, storm, earthquake, hurricane, tornado, vandalism, and theft. What you lose and how you lost it still matter more than what happened politically.

Some losses remain ineligible even when they feel catastrophic in the moment. Normal wear and tear, termites, rust, gradual water intrusion, and slow deterioration are not qualifying events. A drought is usually ineligible unless it triggers a sudden event, such as a mudslide or a collapse. The distinction is often factual, not emotional: was the damage sudden and extraordinary or gradual and expected?

The two preexisting loss limits remain in place. First, there is a $100 reduction for each separate event. Second, your total casualty losses are reduced by 10% of AGI. Both filters remain. If you do not clear these, your casualty loss can be zero even after you do the event-by-event math.

The calculation still flows through Form 4684. The form is the same mechanism you use for federally declared disasters. Nothing changed at the filing engine level, only the qualifying trigger. That is why this rule is easy to implement for the right taxpayer and hard for the wrong one.

Who qualifies for the expanded casualty loss

Eligibility starts with a qualifying event in your tax year. The event must be tied to a disaster declaration. A governor's declaration can now qualify even if there is no presidential declaration. That alone is the biggest difference from the earlier law.

Next, you must own property that suffered damage. The property can be your home or personal-use real estate. The article's focus is on personal property rules, where the casualty loss is still itemized and still subject to the 10% AGI floor.

You also need to prove a loss. That means showing the fair market value before the event and after the event. You need to provide proof of insurance treatment, including any reimbursement expected, allowed, or already paid.

You must itemize deductions. If your return uses the standard deduction, you cannot claim this casualty deduction. This is a high-friction point for many taxpayers. If you are close to itemization, this rule may affect which return method makes sense.

Insurance is often the hardest part of the computation. The statute and IRS guidance treat insurance as prior relief, so you cannot claim a loss for amounts already covered. If your insurer paid and you still claim full loss, your deduction will be reduced or disallowed.

You should also confirm whether your event was recognized as a state or federal disaster by a government declaration.

Casualty loss documentation mistakes on Form 4684

The IRS denies more casualty deductions for weak records than for weak math. Start with proof and then compute. Photos alone usually fail. Photos are not proof of fair market value by themselves. Photos are evidence, not valuation.

Do not use only your own opinion for values. The lower of adjusted basis or FMV decline is sensitive to appraisal assumptions. Use independent support: appraiser reports, market comps, repair invoices, contractor logs, permit records, and photos tied to dates.

Do not combine unrelated events. A hailstorm in spring and a theft in fall are separate events, each with its own $100 floor. Lumping events together can overstate or understate your deduction and invite review.

Do not ignore insurance communications. Save claim numbers, denial letters, appraisals, and negotiation notes. If a claim settles after you file your return, track that outcome because your final tax treatment may need an amendment.

Avoid delayed filing where possible. Under current practice, you usually claim in the disaster year. For federally declared disasters, a prior-year election may still exist in some circumstances. For state disasters under the OBBBA, guidance on prior-year elections remains unclear. The conservative path is to claim in the disaster year and keep records updated.

How to claim casualty loss on Form 4684 in 2026

• Start with the declaration check. If your county is not on an official emergency or disaster list, you cannot rely on this deduction just because the damage is severe.
• Gather evidence by date. Create a timeline from the day before the event through the completion of the repair. Include damage photos, weather alerts, emergency declarations, contractor scopes, invoices, and settlement documents. This timeline makes the event-to-loss link clear.
• File insurance claims before you finalize your tax numbers. If you do not submit a claim, you reduce the credibility of the casualty claim. If a claim is pending at filing, use a conservative expected recovery estimate and document the basis for that estimate.
• Open IRS Publication 547 and use it as a rules map. The core method is still the same as before OBBBA: compute each event, apply the reduction per event, then apply the AGI floor.
• Complete Form 4684 for each item and each event. Put the FMV drop and insurance proceeds in the correct lines. This form can be completed manually, through software, or with a preparer.
• Run a quick threshold check before final filing. If your net casualty losses are modest, the itemized deduction threshold can erase the final benefit. You want to avoid filing two returns and ending up with a loss that never clears the line 4 floor.
• Transfer the result to Schedule A. The casualty amount does not sit on its own. It is attached to the itemized deduction block, and your return still depends on the broader itemization decision.

Calculate casualty loss with $100 and 10% AGI floors

Use a consistent method for each property item. Start with the drop in fair market value caused by the event. That is pre-event FMV minus post-event FMV. For many home repairs, this can align with invoice-based values when repairs restore the home to pre-loss condition.

Then compare that FMV drop to the adjusted basis. You use whichever is lower. If your property has appreciated significantly, the basis and FMV can diverge.

Subtract insurance proceeds. Include all expected and received reimbursements before final tax line entry. The loss for each event is now reduced by the insurance amount, then by the $100 event reduction.

Apply the per-event reductions only. The $100 floor resets for each qualifying event. After you net each event, combine the events and test the aggregate against the 10% AGI floor.

For a partial loss, the unrepaired FMV drop, minus insurance and event floor, may be your starting point. For total loss, you still use the lower-of-rule, usually adjusted basis minus salvage and proceeds, where the property is fully destroyed.

The formula in plain sequence is:

FMV before minus FMV after or adjusted basis, whichever is lower, minus insurance proceeds, minus $100 per event, sum all events, minus 10% of AGI.

Only the remainder is deductible. If the result is negative, the casualty section contributes zero.

Real-world example

A Texas homeowner has a governor-declared disaster in June 2026. A storm damages the home and a detached storage structure. The home was worth $420,000 before and $340,000 after.

The homeowner's adjusted basis is $310,000 for the home and $28,000 for the structure. Insurance sends $50,000 for the home and $20,000 for the building.

Step one: the home FMV drop is $80,000. Lower FMV drop, and the basis is $80,000. Subtracting the $50,000 insurance gives $30,000.

Step two: for the building, use total-loss rules to determine adjusted basis, then subtract insurance. $28,000 minus $20,000 gives $8,000.

Step three: total unreimbursed loss before floors is $38,000. This is a single declared event, so apply a $100 reduction to get $37,900.

Step four: AGI is $150,000, so the 10% floor is $15,000. The final deductible amount is $22,900.

This is reported on Form 4684 and then transferred to Schedule A.

The timing also affects eventual home sale planning. A casualty reduction lowers the adjusted basis, which can increase taxable gain when the home is sold later. For owners looking at a sale timeline, that makes the Sell your home strategy relevant earlier in the decision process.

Your compliance roadmap

Build the process in three stages: evidence, filing, and post-filing monitoring.

For evidence, keep a disaster file containing proof of declaration, valuation materials, invoices, photos, and insurance records. Keep original files and exported digital copies. If your tax preparer asks, you should send a complete packet, not scattered pages.

For filing, check that each event is entered once and that each event gets its own $100 reduction. Confirm the pre-event and post-event values are supported. Confirm insurance has been reduced line-by-line so the form math is clean.

For post-filing, track unresolved claims. If a claim increases later, you may owe additional income or need to amend your return. If a claim decreases, you may need a loss adjustment. Both cases are manageable if the records are organized.

Keep retention. Retain disaster and loss documents for the period relevant to federal and state statute windows. Check your State Tax Deadlines early, so any state follow-through does not get missed.

Filing your return

File the federal return with Form 4684 and itemized deductions completed. If you file via software, most platforms will walk you through the casualty lines when you enable disaster losses.

For a federally declared disaster, you may still elect to claim the loss on a prior year return by amending that return. That election can accelerate the timing of a refund.

For a state-declared disaster under OBBBA, current instructions are less explicit. The conservative approach is to claim in the disaster year and monitor IRS updates on any election expansion or clarification.

If your tax position also results in a net operating loss, the interplay between the two is separate and can be complex. Get a tax professional involved early to avoid mixing casualty sequencing with broader year-end NOL calculations.

Property tax strategies after a disaster loss

A casualty loss can change your broader property tax picture. Use it with other strategies, not instead of others.

The Sell your home strategy helps you model gain impact after basis adjustments.

The Augusta rule can generate additional income beyond disaster-year losses and may improve your broader AGI planning.

A Traditional 401k contribution lowers AGI, which directly affects the 10% casualty floor. If AGI is lower, more loss can survive the threshold.

The Oil and gas deduction is a separate deduction path for eligible taxpayers and can be paired in a year where casualty timing also exists.

These strategies should not be managed in isolation. Instead's platform helps Individuals combine disaster deductions with life-stage plans, home sale timing, and retirement strategy.

Document your disaster loss before the deduction window closes

Casualty loss deductions under OBBBA Sec. 70109 now cover governor-declared state disasters that do not receive a separate federal declaration. However, the deduction still requires a clean calculation: lower of adjusted basis or FMV decline, minus insurance, minus the $100 floor, minus 10% of AGI. Basis adjustments from insurance proceeds also affect future capital gain on a sale, so the math touches multiple years of returns. Instead, walks you through the full casualty loss calculation, adjusts your property basis correctly, and flags the downstream impact on any future home-sale gain. Hence, you are not surprised at the closing.

Review Instead's pricing plans to start documenting your casualty loss deduction.

Frequently asked questions

Q: What qualifies as a state disaster for casualty loss under OBBBA?

A: A qualifying disaster is one covered by a federal or governor declaration where the property damage is sudden and unexpected. Official declaration records and evidence of financial loss must support the event.

Q: Can I file a casualty loss on my prior year return for a state disaster?

A: The federal prior-year election is available in some federally declared cases. For state-declared disasters under OBBBA, guidance is still emerging, so the practical approach is to claim in the year of the disaster.

Q: How do insurance proceeds reduce your casualty loss deduction?

A: Insurance reduces the loss dollar for dollar. Reimbursements received or expected are subtracted before any floor reductions. If the final settlement changes, you adjust the return in the year the change is finalized.

Q: Do all homeowners automatically qualify for the casualty loss deduction?

A: No. You must have a qualifying sudden casualty event, property records, and an itemized return. If your deduction does not clear the $100 event floor and 10% of AGI floor, the final amount can be zero.

Q: Are partial and total property losses calculated the same on Form 4684?

A: Both are deductible, but they are valued differently. Partial losses use the lesser of basis or FMV decline after repairs. Total losses focus on adjusted basis rules and salvage treatment.

Q: Does a casualty loss deduction increase capital gains when I sell the property?

A: Yes, because the loss reduction lowers the adjusted basis. If you sell later, that lower basis increases taxable gain unless another relief rule, such as replacement treatment under Section 1033, applies.