Wash. Rev. Code § 4.16.070
No action for the recovery of any real estate sold by an executor or administrator under the laws of this state shall be maintained by any heir or other person claiming under the deceased, unless it is commenced within five years next after the sale, and no action for any estate sold by a guardian shall be maintained by the ward, or by any person claiming under him or her, unless commenced within five years next after the termination of the guardianship, except that minors, and other persons under legal disability to sue at the time when the right of action first accrued, may commence such action at any time within three years after the removal of the disability.
RCW 4.16.070
Age of majority: Chapter 26.28 RCW.
Probate
actions by and against executors, etc.: Chapter 11.48 RCW.
sales and mortgages of real estate: Chapter 11.56 RCW; RCW 11.60.010.
Sales not voided by irregularities: RCW 11.56.115.