Wash. Rev. Code § 35.50.005
Within fifteen days after any city or town has ordered a local improvement and created a local improvement district, the city or town shall cause to be filed with the officer authorized by law to collect the assessments for such improvement, the title of the improvement and district number and a copy of the diagram or print showing the boundaries of the district and preliminary assessment roll or abstract of same showing thereon the lots, tracts and parcels of land that will be specially benefited thereby and the estimated cost and expense of such improvement to be borne by each lot, tract, or parcel of land. Such officer shall immediately post the proposed assessment roll upon his or her index of local improvement assessments against the properties affected by the local improvement.
RCW 35.50.005