Wash. Rev. Code § 85.06.090
Whenever it is desired to prosecute the construction of a system of drainage by said drainage district, said district, by and through its board of commissioners, shall file a petition in the superior court of the county in which said district is located, setting forth therein the route and termini of said system, with a complete description thereof, together with specifications for its construction, with all necessary plats and plans thereof, with draughts of any artificial appliances or equipment necessary in aid thereof, together with the estimated cost of such proposed improvement, showing therein the names of the landowners whose lands are to be benefited by such proposed improvement; the number of acres owned by each landowner, and the maximum amount of benefits per acre to be derived by each landowner set forth therein from the construction of said proposed improvement, and that the same will be conducive to the public health, convenience and welfare, and increase the value of all of said property for purposes of public revenue. Said petition shall further set forth the names of the landowners through whose land the right-of-way is desired for said improvement; the amount of land necessary to be taken therefor, and an estimate of the value of said lands so sought to be taken for such right-of-way, and the damages sustained by any person or corporation interested therein, if any, by reason of such appropriation, irrespective of any benefits to be derived by such landowners by reason of the construction of said improvement. Such estimate shall be made, respectively, to each person through whose land said right-of-way is sought to be appropriated. Said petition shall set forth as defendants therein all the persons or corporations to be benefited by said improvement, and all persons or corporations through whose land the right-of-way is sought to be appropriated, and all persons or corporations having any interest therein, as mortgagee or otherwise, appearing of record, and shall set forth that said proposed system of drainage is necessary to drain all of said lands described in said petition, and that all lands sought to be appropriated for said right-of-way are necessary to be used as a right-of-way in the construction and maintenance of said improvement; and when the proposed improvement will protect or benefit the whole or any part of any public or corporate road or railroad, so that the traveled track or roadbed thereof will be improved by its construction, such fact shall be set forth in said petition, and such public or private corporations owning said road or railroad shall be made parties defendant therein, and the maximum amount of benefits to be derived from said proposed improvement shall be estimated in said petition against said road or railroad: PROVIDED, HOWEVER, That all maps, plats, field notes, surveys, plans, specifications, or other data heretofore made, ascertained or prepared under laws heretofore enacted on the subject of this chapter, may be used under the provisions of this chapter.
RCW 85.06.090