Cal. Pub. Resources Code § 13217
If any water or sewer standby or immediate availability charge remains unpaid on the first day of the month in which the board of supervisors of the county in which the district is located is required by law to levy the amount of taxes required for county purposes, a 6-percent penalty thereon shall accrue. The amount of the unpaid charges plus the penalty shall constitute a special assessment upon the land with respect to which the services, for which charges are unpaid, were available or in existence on a standby basis, and shall constitute a lien on that land. The assessment shall be collected at the same time and in the same manner as ad valorem taxes are collected and shall be subject to the same penalties and the same procedures upon sale in the case of delinquency as provided for such taxes. All laws applicable to the levy, collection, and enforcement of ad volorem taxes shall be applicable to the assessment; except that if any real property to which such lien would attach has been transferred or conveyed to a bona fide purchaser for value, or if a lien of a bona fide encumbrancer for the value has been created and attaches thereon, prior to the date on which the first installment of such taxes would become delinquent, then the lien which would otherwise be imposed by this section shall not attach to such real property and the unpaid charges, and any penalty thereon, relating to such property shall be transferred to the unsecured roll for collection.
At least 15 days before the first day of the month in which the board of supervisors is required by law to levy the amount of taxes required for county purposes, the district board shall furnish in writing both to the board of supervisors and to the county auditor, a description of each parcel of land within the district upon which a standby or immediate availability charge or charges remains unpaid, together with a statement setting forth both the amount of the unpaid charge or charges and the amount of the penalty on each parcel of land.
Ca. Pub. Res. Code § 13217