Wash. Rev. Code § 84.36.047
The following property shall be exempt from taxation:
Real and personal property owned by or leased to any nonprofit corporation or association and, except as provided in RCW 84.36.805, used exclusively to rebroadcast, amplify, or otherwise facilitate the transmission and/or reception of radio and/or television signals originally broadcast by foreign or domestic governmental agencies for reception by the general public: PROVIDED, That in the event such property is leased, the benefit of the exemption shall inure to the user.
RCW 84.36.047
Effective date-Construction-1977 ex.s. c 348: "This act is necessary for the immediate preservation of the public peace, health and safety, the support of the state government and its existing public institutions, shall take effect immediately and shall be effective for assessment in 1977 for taxes due and payable in 1978." [ 1977 ex.s. c 348 s 3.]