Washington Revised Code Title 7. Special Proceedings and Actions § 7.75.040. Dispute resolution agreement required--When admissible as evidence

(a) That the disputing parties enter into a written agreement which expresses the method by which they shall attempt to resolve the issues in dispute; and

(b) That at the conclusion of the dispute resolution process, the parties enter into a written agreement which sets forth the settlement of the issues and the future responsibilities, if any, of each party.