Wash. Rev. Code § 35.72.020
(1) Except as otherwise provided in subsection (2) of this section, the contract may provide for the partial reimbursement to the owner or the owner's assigns for a period not to exceed fifteen years of a portion of the costs of the project by other property owners who:
(2)
[ 2006 c 88 s 1; 1983 c 126 s 2.]