Wash. Rev. Code § 59.18.240
So long as the tenant is in compliance with this chapter, the landlord shall not take or threaten to take reprisals or retaliatory action against the tenant because of any good faith and lawful:
(2) Assertions or enforcement by the tenant of his or her rights and remedies under this chapter. "Reprisal or retaliatory action" shall mean and include but not be limited to any of the following actions by the landlord when such actions are intended primarily to retaliate against a tenant because of the tenant's good faith and lawful act:
[ 2010 c 8 s 19025; 1983 c 264 s 9; 1973 1st ex.s. c 207 s 24.]