Wash. Rev. Code § 87.80.030
The petition for the creation of a board of joint control shall be addressed to the board of county commissioners, shall describe generally the relationship, if any, of the irrigation entities to an established federal reclamation project, the primary waterworks of the entities including reservoirs, main canals, hydroelectric facilities, pumping stations, and drainage facilities, giving them their local names, if any they have, and shall show generally the physical relationship of the lands being watered from the water facilities. However, lands included in any irrigation entity involved need not be described individually but shall be included by stating the name of the irrigation entity and all the irrigable lands in the irrigation entity named shall by that method be deemed to be involved unless otherwise specifically stated in the petition. Further, the petition must propose the formula for board of joint control apportionment of costs among its members, and may propose the composition of the board of joint control as to membership, chair, and voting structure. When a board of joint control includes irrigation entities other than an irrigation district or an operating entity for a division within a federal reclamation project as provided in RCW 87.80.005, the voting structure must be such that the votes apportioned to those entities are less than fifty percent of the total votes.
The petition shall also state generally the reasons for the creation of a board of joint control and any other matter the petitioners deem material, and shall allege that it is in the public interest and to the benefit of all the owners of the lands receiving water within the area of jurisdiction, that the board of joint control be created and request that the board of county commissioners consider the petition and take the necessary steps provided by law for the creation of a board of joint control. The petition shall be accompanied by a map showing the area of jurisdiction and the general location of the water supply and distribution facilities.
RCW 87.80.030