Wash. Rev. Code § 36.70.600
The recommendation to the board of any official control or amendments thereto by the planning agency shall be by the affirmative vote of not less than a majority of the total members of the commission. Such approval shall be by a recorded motion which shall incorporate the findings of fact of the commission and the reasons for its action and the motion shall refer expressly to the maps, descriptive and other matters intended by the commission to constitute the plan, or amendment, addition or extension thereto. The indication of approval by the commission shall be recorded on the map and descriptive matter by the signatures of the chair and the secretary of the commission and of such others as the commission in its rules may designate.
RCW 36.70.600