Personal property tax is due on most property used in conducting business. In Washington State, personal property refers to assets used in conducting a business, other than real estate.Personal property tax is due April 30th. All businesses in the state are responsible for filing a listing of their personal property each year with their county Assessor. Washington State provides the following exemptions from personal property tax (RCW 84.36). • Household goods and personal effects, unless used in a business. In Washington State, the listing of business personal property is a self-reporting system. Personal property asset listings can be electronically filed through the county assessor's website. Contact us when you start your business to set up an account.