Wash. Rev. Code § 28B.07.050
(2) The bonds may be secured by:
(4) Any bond resolution, trust indenture, or agreement with a participant relating to bonds issued by the authority or the financing or refinancing made available by the authority may contain provisions, which may be made a part of the contract with the holders or owners of the bonds to be issued, pertaining to the following, among other matters:
[ 2003 c 84 s 1; 1983 c 169 s 5.]