Wash. Rev. Code § 42.17A.345
(1) Each commercial advertiser who has accepted or provided political advertising or electioneering communications during the election campaign shall maintain current books of account and related materials as provided by rule that shall be open for public inspection during normal business hours during the campaign and for a period of no less than five years after the date of the applicable election. The documents and books of account shall specify:
[ 2019 c 428 s 26; 2010 c 204 s 508; 2005 c 445 s 8; 1975-'76 2nd ex.s. c 112 s 5; 1973 c 1 s 11 (Initiative Measure No. 276, approved November 7, 1972). Formerly RCW 42.17.110.]
Effective date—Finding—Intent—2019 c 428: See notes following RCW 42.17A.160.