California Code, Government Code - GOV § 54347

(a) The granting of discounts for prompt payment of bills.

(b) The requiring of deposits or the prepayment of charges in an amount not exceeding one year's charges either from persons receiving service and using the facilities of the enterprise or from the owners of property on which or in connection with which said services and facilities are to be used; provided, however, that in case of nonpayment of all or part of a bill said deposits or prepaid charges shall be applied only insofar as necessary to liquidate the cumulative amount of such charges plus penalties and costs of collection.

(c) The requiring of a guaranty by the owner of property that the bills for service to said property or the occupants thereof will be paid.