Gov. Code, § 54346.4

(a) A local agency whose jurisdiction is geographically coextensive with the county in which it operates, acquires, constructs, or improves a system, plan, works, facilities, or undertaking for the collection, treatment, or disposal of storm water, including drainage, may, with the concurrence of the county, provide for the collection of the agency’s charges in the same manner, and subject to the same penalties and priority of lien as, other charges and taxes fixed and collected by, or on behalf of the local agency. However, if, for the first year the charges are prescribed, the property served by the agency has been transferred or conveyed to a bona fide purchaser for value, and attached thereon, prior to the date on which the first installment of county taxes would become delinquent, the charge shall not result in a lien against the real property but shall be transferred to the unsecured roll.

(b) If the charges are collected by the county, the county may deduct its reasonable costs incurred for the service before remittal of the balance to the local agency’s treasury.