Washington Revised Code Title 35A. Optional Municipal Code § 35A.14.010. Authority for annexation

Any portion of a county not incorporated as part of a city or town but lying contiguous to a code city may become a part of the charter code city or noncharter code city by annexation. An area proposed to be annexed to a charter code city or noncharter code city shall be deemed contiguous thereto even though separated by water or tide or shore lands and, upon annexation of such area, any such intervening water and/or tide or shore lands shall become a part of such annexing city.