A Casualty Loss is a deductible loss of property resulting from a sudden, unexpected, or unusual event such as a natural disaster, fire, theft, vandalism, or accident. Prior to 2018, casualty losses could be deducted as itemized deductions when they exceeded certain thresholds. However, the Tax Cuts and Jobs Act significantly restricted this deduction, limiting it to losses occurring in federally declared disaster areas for tax years 2018 through 2025.
Under current law, personal casualty losses are only deductible if they occur in an area declared a federal disaster by the President. Business or income-producing property casualty losses remain deductible regardless of disaster area status. The loss must result from an identifiable event that is sudden (not gradual deterioration), unexpected (not reasonably anticipated), and unusual (not a day-to-day occurrence). Qualifying events include hurricanes, tornadoes, floods, wildfires, earthquakes, terrorist attacks, vandalism, car accidents, and theft. Progressive deterioration, insect damage, and normal wear and tear do not qualify.
Calculating a casualty loss involves determining your adjusted basis in the property (generally what you paid plus improvements), establishing the property’s fair market value immediately before and after the casualty, using the lesser of basis or FMV decrease as your loss amount, subtracting any insurance reimbursement, reducing the loss by $100 per casualty event, and then reducing the total by 10% of your adjusted gross income. Only the amount exceeding these thresholds is deductible.
Substantiation requires documenting the type and date of casualty, proof the loss resulted from the casualty, proving you owned the property, property value before and after (often requiring professional appraisals for significant losses), and insurance claims and reimbursements. The IRS may challenge casualty loss deductions without adequate documentation.
If casualty gains exceed casualty losses in the same year, the losses and gains are netted, potentially resulting in taxable gain. Casualty losses are claimed on Form 4684 (Casualties and Thefts), with the deductible amount transferred to Schedule A. Timely filing of insurance claims is essential, as you cannot claim losses for which you fail to pursue reimbursement.