Wash. Rev. Code § 54.16.032
Any district is hereby authorized, within limits established by the Constitution of the state of Washington, to assist the owners of structures in financing the acquisition and installation of fixtures, systems, and equipment, for compensation or otherwise, for the conservation or more efficient use of water in the structures under a water conservation plan adopted by the district if the cost per unit of water saved or conserved by the use of the fixtures, systems, and equipment is less than the cost per unit of water supplied by the next least costly new water source available to the district to meet future demand. Except where otherwise authorized, assistance shall be limited to:
Pay back shall be in the form of incremental additions to the utility bill, billed either together with use charge or separately. Loans shall not exceed two hundred forty months in length.
RCW 54.16.032
Intent-Contingent effective date-1989 c 421: See notes following RCW 35.92.017.