Cal. Water Code § 46280

When the secretary of the board files the certificates as provided for by Section 46209, or if objections are filed, when the board files with the county treasurer of an affected county the assessment roll as finally approved by the adjustment board, the charges assessed thereby upon the several tracts of land in the county shall constitute a lien thereon which is prior to all other liens except state, county, and municipal taxes, and assessments or taxes levied or assessed by or under statutory authority. The filing in either case imparts notice to all persons.