Public Utilities Code § 105213
ARTICLE 1. Authorization and Issuance of General Obligation Bonds
The board may enter into any covenants deemed proper to provide for issuance of additional parity bonds and the priority and pledge of special taxes; and any other covenants that are customary or desirable in the issuance of any bonds payable out of special funds or that are 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.