Wash. Rev. Code § 5.60.070
(1) If there is a court order to mediate, a written agreement between the parties to mediate, or if mediation is mandated under RCW 7.70.100, then any communication made or materials submitted in, or in connection with, the mediation proceeding, whether made or submitted to or by the mediator, a mediation organization, a party, or any person present, are privileged and confidential and are not subject to disclosure in any judicial or administrative proceeding except:
(2) When there is a court order, a written agreement to mediate, or when mediation is mandated under RCW 7.70.100, as described in subsection (1) of this section, the mediator or a representative of a mediation organization shall not testify in any judicial or administrative proceeding unless:
[ 2005 c 172 s 14; 1993 c 492 s 422; 1991 c 321 s 1.]
Short title—Effective date—2005 c 172: See RCW 7.07.900 and 7.07.904.
Findings—Intent—1993 c 492: See notes following RCW 43.20.050.
Short title—Savings—Reservation of legislative power—Effective dates—1993 c 492: See RCW 43.72.910 through 43.72.915.
Severability—1991 c 321: "If any provision of this act or its application to any person or circumstance is held invalid, the remainder of the act or the application of the provision to other persons or circumstances is not affected." [ 1991 c 321 s 3.]