Understanding the Tax Implications and Proofs Required for Residential Casualty Losses1981-01-01unknownhttp://rightsstatements.org/vocab/NKC/1.0/enghttp://congressarchives.org/record/CAC_CC_109_4_22_2_0015Casualty losses for nonbusiness property must exceed $100 and result from a sudden, unexpected, or unusual event to be deductible. Losses from drought may not qualify as casualty losses unless there is evidence of rapid and severe subsoil shrinkage. The amount deductible is the difference in fair market value before and after the loss, not exceeding the adjusted basis of the property. Professional engineering opinions and appraisals are necessary to prove the extent of damage, and all opinions and appraisals are subject to IRS review.