Such board of supervisors shall thereupon promptly cause a certified copy of the order declaring such power district created to be filed in the office of the secretary of state. A certified copy of such order shall also be filed with the clerk of each municipality included in the proposed district, and with the clerk of the board of supervisors of each county, any unincorporated part of which is included in the proposed district. From and after the filing of such copy of the order with the secretary of state, the creation and incorporation of such district shall be deemed complete.