Wash. Rev. Code § 41.35.140
Any person aggrieved by any decision of the department affecting his or her legal rights, duties, or privileges must, before he or she appeals to the courts, file with the director by mail or personally within sixty days from the day the decision was communicated to the person, a notice for a hearing before the director's designee. The notice of hearing shall set forth in full detail the grounds upon which the person considers the decision unjust or unlawful and shall include every issue to be considered by the department, and it must contain a detailed statement of facts upon which the person relies in support of the appeal. These persons shall be deemed to have waived all objections or irregularities concerning the matter on which the appeal is taken, other than those specifically set forth in the notice of hearing or appearing in the records of the retirement system.
RCW 41.35.140