Cal. Pub. Util. Code § 103513

If bonds are authorized that contain a provision for special taxes under subdivision (i) of Section 103500, the board may enter into such covenants as may be deemed proper to provide for issuance of additional parity bonds, the priority and pledge of special taxes and such other covenants as are customary or desirable in the issuance of any bonds payable out of special funds or necessary, convenient, or desirable to secure the bonds or tending to make them more marketable, subject to the provisions of the ordinance calling the bond election.