Pub. Util. Code, § 31404

A certificate of proceedings shall be made by the secretary of the district and filed with the Secretary of State. Upon the filing thereof in the office of the Secretary of State, the corporate area of such city as of the date of the election or such unincorporated county territory shall become, and be, an integral part of the district, and the taxable property therein shall be subject to taxation thereafter for all purposes of the district, including, without limitation, the payment of bonds and other obligations of the district at the time authorized or outstanding, and the board of directors of the district shall be empowered to do all things necessary to enforce and make effective the terms and conditions of annexation fixed as hereinabove authorized.