RCW 82A.04.340: Taxable income—Wagering losses.

In computing a taxpayer's Washington taxable income, the taxpayer must deduct an amount equal to 90 percent of any Washington allocated wagering losses for the tax year. The amount of the losses deducted cannot be more than the Washington allocated wagering income included in the taxpayer's Washington base income. Wagering losses may not be carried forward or backward. The wagering loss deduction must be adjusted for nonresidents as provided in RCW 82A.04.410.