Cal. Water Code § 81438

(a) In addition to the authority granted in Section 81435, the agency may do all of the following: (1) Impose reasonable rates, fees, and charges on BAWSCA members for any program or service provided or work performed by the agency. (2) Impose rates, fees, and charges on BAWSCA members and any entity that subsequently serves a BAWSCA member’s service area in an amount as shall be necessary, together with other available sources of funds, to pay debt service on any bonds issued by the agency for a use authorized by Section 81437.5 and to satisfy all other obligations of the agency related to these bonds, including, but not limited to, funding and maintaining reserve funds and complying with financial covenants. (3) Distribute any amounts collected that are not needed for the purposes of this article to BAWSCA members. (b) If requested by the agency, the City and County of San Francisco shall collect any rates, fees, and charges imposed by the agency pursuant to this section as a surcharge under the July 2009 Water Supply Agreement. These amounts shall be collected in a manner, and with remedies for nonpayment, specified in an agreement between the agency and the City and County of San Francisco.