Washington Revised Code Title 90. Water Rights--Environment § 90.16.110. Water for use outside state

Whenever the use of water shall be necessary for domestic, manufacturing, irrigation, or in interstate transportation at or for any incorporated or unincorporated city, town, village or hamlet situated partly in Washington and partly in an adjoining state or where any city, town, village or hamlet is incorporated on one side of the state line and there are inhabitants living in adjacent and contiguous territory on the other side, it shall be lawful for any person, association or corporation to locate, appropriate, divert and deliver any of the unappropriated public waters of this state necessary for the use of such city, town, village or hamlet and the inhabitants thereof and those residing in and embracing such contiguous territory both within this state and such adjoining state; and locations may be made and authority is hereby granted for such purpose the same as for any other appropriation within the state and a diversion and delivery for such purpose shall have the same force and effect as if made for use wholly within this state and any appropriation, diversion or use heretofore made for such purpose shall be deemed as valid and legal as if made for a use wholly within this state and priority thereof shall date from the appropriation and diversion the same as if it had been made for use wholly within this state.