Wash. Rev. Code § 17.28.040
Upon receipt of a duly certified petition, the board of commissioners shall cause the text of the petition to be published once a week for at least three consecutive weeks in one or more newspapers of general circulation within the county where the petition is presented and at each city a portion of which is included in the proposed district. If any portion of the proposed district lies in another county, the petition and notice shall be likewise published in that county.
Only one copy of the petition need be published even though the district embraces more than one unit. No more than five of the names attached to the petition need appear in the publication of the petition and notice, but the number of signers shall be stated.
With the publication of the petition there shall be published a notice of the time of the meeting of the county commissioners when the petition will be considered, stating that all persons interested may appear and be heard.
RCW 17.28.040