Wash. Rev. Code § 77.15.077
Washington fish and wildlife officers may engage in private law enforcement off-duty employment, in uniform or in plainclothes for private benefit, subject to guidelines adopted by the chief of fish and wildlife enforcement. These guidelines must ensure that the integrity and professionalism of the Washington fish and wildlife enforcement is preserved. Use of Washington fish and wildlife officer's uniforms shall be considered de minimis use of state property. For any employment authorized under this section that occurs on reservation, trust, or allotted lands of a federally recognized Indian tribe, a Washington fish and wildlife officer must have taken the violence de-escalation and mental health training provided by the criminal justice training commission, including the curriculum of the history of police interactions with Native American communities; and the private employer must have obtained permission from the affected federally recognized Indian tribe.
RCW 77.15.077