Wash. Rev. Code § 35A.14.040
Within ten days after receipt of a petition or resolution calling for an election on the question of annexation, the county annexation review board shall meet and, if the proposed annexation complies with the requirements of law, shall fix a date for a hearing thereon, to be held not less than fifteen days nor more than thirty days thereafter, of which hearing the city must give notice by publication at least once a week for two weeks prior thereto in one or more newspapers of general circulation within the city and in one or more newspapers of general circulation within the area proposed to be annexed. The hearing shall be held within the city to which the territory is proposed to be annexed, at a time and place to be designated by the board. Upon the day fixed, the board shall conduct a hearing upon the petition or resolution, at which hearing a representative of the city shall make a brief presentation to the board in explanation of the annexation and the benefits to be derived therefrom, and the petitioners and any resident of the city or the area proposed to be annexed shall be afforded a reasonable opportunity to be heard. The hearing may be adjourned from time to time in the board's discretion, not to exceed thirty days in all from the commencement of the hearing.
RCW 35A.14.040