Washington State residency definition

Individuals who are residents of this state on more than a temporary or transient basis are subject to sales and use tax. An individual may be considered a resident of this state even though they are a resident of another state. 

The Department of Revenue presumes that a person is a resident of this state if they do any of the following: 

• Maintains a residence in Washington for personal use.
• Lives in a motor home or vessel which is not permanently attached to any property if the person previously lived in this state and does not have a permanent residence in any other state.
• Is registered to vote in this state.
• Receives benefits under one of Washington's public assistance programs.
• Has a state professional or business license in this state.
• Is attending school in this state and paying tuition as a Washington resident or is a custodial parent with a child attending a public school in this state.
• Uses a Washington address for federal or state taxes.
• Has a Washington State driver's license.
• Claims Washington as a residence for obtaining a hunting or fishing license.
• Claims Washington as a residence for eligibility to hold public office or for judicial actions.

A person can deny being a resident if they provide other facts that show they don't plan to live in Washington, either temporarily or permanently. However, someone who currently lives in Washington and plans to move later is still considered a resident.

Reference  

WAC 308-99-020 – Definitions.