Casual or isolated sales are not subject to Washington business and occupation (B&O) tax. Such sales are subject to sales tax if the sale is made by a person required to be registered with the Department. Sales to a consumer must be reported under both retailing B&O tax and retail sales tax. A "casual sales" deduction may be claimed under retailing B&O tax. Casual or isolated sales to customers providing a reseller permit must be reported under the wholesaling B&O tax. A casual sales deduction may then be claimed under wholesaling B&O tax. Casual or Isolated Sales, Washington Department of Revenue, July 8, 2026