Wash. Rev. Code § 2.10.190
Any person aggrieved by any final decision of the retirement board must, before petitioning for judicial review, file with the director of the retirement system by mail or personally within sixty days from the day such decision was communicated to such person, a notice for a hearing before the retirement board. The notice of hearing shall set forth in full detail the grounds upon which such person considers such decision unjust or unlawful and shall include every issue to be considered by the retirement board, and it must contain a detailed statement of facts upon which such person relies in support thereof. Such persons shall be deemed to have waived all objections or irregularities concerning the matter on which such appeal is taken other than those records of the retirement system.
RCW 2.10.190