Wash. Rev. Code § 36.94.110
After adoption of the sewerage and/or water general plan, all municipal corporations and private utilities within the plan area shall abide by and adhere to the plan for the future development of their systems. A municipal corporation or private utility, including a wastewater company as defined in RCW 80.04.010, may petition for amendments to the plan. Whenever the governing authority of any county or counties or any municipal corporation deems it to be for the public interest to amend the sewerage and/or water general plan for such county or counties, notice must be filed with the board or boards of county commissioners. Upon such notice, the board or boards shall initiate consideration of any amendment requested relating to the plan and proceed as provided in this chapter for the adoption of an original plan.
RCW 36.94.110
Findings-Purpose-Limitation of chapter-Effective date- 2011 c 214 : See notes following RCW 80.04.010.