Wash. Rev. Code § 36.61.230
The special assessment or annual special assessments imposed upon the respective lots, tracts, parcels of land, and other property in the special assessment roll or annual special assessment roll confirmed by resolution of the county legislative authority for the purpose of paying the cost and expense in whole or in part of any lake or beach improvement or maintenance activities shall be a lien upon the property assessed from the time the special assessment roll is placed in the hands of the county treasurer for collection, but as between the grantor and grantee, or vendor and vendee of any real property, when there is no express agreement as to payment of the special assessments against the real property, the lien of such special assessments shall attach thirty days after the filing of the diagram or print and the estimated cost and expense of such lake or beach improvement or maintenance activities to be borne by each lot, tract, parcel of land, or other property, as provided in RCW 36.61.220. Interest and penalty shall be included in and shall be a part of the special assessment lien. No lien shall extend to public property subjected to special assessments.
The special assessment lien shall be paramount and superior to any other lien or encumbrance theretofore or thereafter created except a lien for general taxes.
RCW 36.61.230