RCW 35.13.150: Direct petition method—Ordinance providing for annexation.

Following the hearing, the council or commission shall determine by ordinance whether annexation shall be made. Subject to RCW 35.02.170 , they may annex all or any portion of the proposed area but may not include in the annexation any property not described in the petition. Upon passage of the ordinance a certified copy shall be filed with the board of county commissioners of the county in which the annexed property is located.