Any due and payable assessment not paid by the milk plant operator by the 20th of the succeeding month shall be considered a lien on any property owned by them. All delinquent assessments shall be filed as liens quarterly by the director with the county auditor of any county in which property owned by the milk plant operator is located. All delinquent assessments shall be collected in the manner and with the same priority over other creditors as prescribed for the collection of delinquent taxes under chapters 84.60 and 84.64 RCW.