Wash. Rev. Code § 34.05.001
The legislature intends, by enacting this 1988 Administrative Procedure Act, to clarify the existing law of administrative procedure, to achieve greater consistency with other states and the federal government in administrative procedure, and to provide greater public and legislative access to administrative decision making. The legislature intends that to the greatest extent possible and unless this chapter clearly requires otherwise, current agency practices and court decisions interpreting the Administrative Procedure Act in effect before July 1, 1989, shall remain in effect. The legislature also intends that the courts should interpret provisions of this chapter consistently with decisions of other courts interpreting similar provisions of other states, the federal government, and model acts.
RCW 34.05.001