Cal. Gov. Code § 54346.3

The local agency may enter into a written contract with any person, firm or public or private corporation providing for the billing and collection by such person, firm or corporation of the charges for the facilities, service or water furnished by any enterprise. If all or any part of any bill rendered by any such person, firm or corporation pursuant to any such contract is not paid and if such person, firm or corporation renders any public utility service to the person billed, such person, firm or corporation may discontinue its utility service until such bill is paid, and the contract between the local agency and such person, firm or corporation may so provide.