Wash. Rev. Code § 26.14.180
(1) On motion of a party, the court shall vacate an unconfirmed award if the moving party establishes that:
(b) There was:
(2) Except as otherwise provided in subsection (3) of this section, on motion of a party, the court shall vacate an unconfirmed award that determines a child-related dispute if the moving party establishes that:
(5) A motion under this section to vacate or amend an award must be filed not later than ninety days:
[ 2023 c 61 s 19.]