Wash. Rev. Code § 88.24.030
Whenever any person or persons shall be desirous of erecting a wharf at the terminus of any street of any incorporated town or city in the state, he or she or they may apply to the municipal authorities of such town or city who, if they shall be satisfied that the public convenience requires said wharf, may authorize the same to be erected and kept in repair for any length of time not exceeding ten years; and every person building, owning or occupying a wharf in this state, upon which wharfage is charged and received, shall be held accountable to the owner or owners, consignees or agents, for any and all damage done to property stored upon, or passing over said wharf, in consequence of the unfinished, incomplete, or insufficient condition of said wharf; and every such person shall post or cause to be posted in a conspicuous place on said wharf the established rates of wharfage, noting passengers and their baggage free.
RCW 88.24.030