Cal. Wat. Code § 36524
The board of the district may provide for any maintenance and operation of the distribution system of a distribution district that may be required by the provisions of the contract between the distribution district and the United States under the federal reclamation laws or under the contract between the distribution district and the district, from funds raised by charges which are fixed and collected for the use of water or for any other such service furnished by means of the distribution system, in the same manner and with the same effect as charges are made and collected by district for the use of water or for services. Such charges may be in addition to other charges made by the district for the furnishing of water or other services.
Ca. Water Code § 36524