Washington Revised Code Title 82. Excise Taxes § 82.04.220. Business and occupation tax imposed

(2)(a) A person who establishes or reestablishes a substantial nexus with this state after the first day of the current calendar year under the provisions of RCW 82.04.067 is subject to the tax imposed under this chapter for the current calendar year only on business activity occurring on and after the date that the person established or reestablished a substantial nexus with this state in the current calendar year.

(b) The provisions of (a) of this subsection do not apply to a person who met any of the criteria in RCW 82.04.067(1) (a) through (c) during the immediately preceding calendar year, and such person is taxable under this chapter for the current calendar year in its entirety.