Wash. Rev. Code § 36.61.220
Within thirty days after a county creates a lake or beach management district, the county shall cause to be filed with the county treasurer, a description of the lake or beach improvement and maintenance activities proposed that the lake or beach management district finances, the lake or beach management district number, and a copy of the diagram or print showing the boundaries of the lake or beach management district and preliminary special assessment roll or abstract of the same showing thereon the lots, tracts, parcels of land, and other property that will be specially benefited thereby and the estimated cost and expense of such lake or beach improvement and maintenance activities to be borne by each lot, tract, parcel of land, or other property. The treasurer shall immediately post the proposed special assessment roll upon his or her index of special assessments against the properties affected by the lake or beach improvement or maintenance activities.
RCW 36.61.220