Allows taxpayers who claimed a tax deduction for a casualty loss to a principal residence resulting from Hurricanes Katrina, Rita, or Wilma and then received a grant as reimbursement for such loss in a subsequent taxable year to file an amended income tax return and reduce such tax deduction by the amount of the reimbursement. Waives interest and penalties on any underpayment of tax resulting from the reduced tax deduction if such underpayment is paid within one year of the filing of the amended tax return.