Wash. Rev. Code § 36.88.290
An action to collect any special assessment or installment thereof for road improvements, or to enforce the lien of any such assessment or installment, whether such action be brought by the county or by the holder of any certificate of delinquency, or by any other person having the right to bring such action, shall be commenced within ten years after such assessment shall have become delinquent or within ten years after the last installment of any such assessment shall have become delinquent, when said special assessment is payable in installments.
Actions to set aside or cancel any deed issued after midnight, June 6, 1951, upon the sale of property for road improvement assessments, or for the recovery of property sold for delinquent road improvement assessments must be brought within three years from and after date of the issuance of such deed.
RCW 36.88.290