Cal. Health & Safety Code § 5063

The income received by the owner-district under the contract shall, if so provided in the ordinance, be deemed to be a part of the revenue of the works. The owner-district shall deduct from the whole cost and expenses such part as shall be paid by the lessee-district pursuant to the provision of the contract; but no rates shall be imposed or collected from the users of the works or portions thereof except in cases where the works or portions thereof have been acquired by means of the bonds, and unless additional benefits will be derived by the users as a result of the contract. In that case the rates shall be only sufficient to cover the value of the additional benefits.