Wash. Admin. Code § 458-12-155
Before assessing personal property located on federally-owned lands, the assessor shall determine whether the federal government claims exclusive or concurrent jurisdiction over the land. If exclusive jurisdiction is claimed, such land shall be treated as not even existing in the state of Washington for taxation purposes. (Concessions Company v. Morris, 109 Wash. 46 (1919); Ryan v. State, 188 Wash. 115 (1936); AGO 1933-1934, p. 298; PTB No. 211 (1951)) Personal property, including leasehold interests, located upon such lands shall not be subject to taxation.
If the federal government holds the land concurrently with the state, personal property, including leasehold interests located on or in such land, is subject to taxation. (AGO 1933-34, p. 298; AGO 1945-46, p. 717; PTB No. 211 (1951).)
Wash. Admin. Code § 458-12-155
Order PT 68-6, § 458-12-155, files 4/29/68.