The officers of election shall make a return of the election to the board of supervisors, which shall canvass the returns as provided by law. If a majority of the votes cast at the election are in favor of creating the district the board of supervisors shall make and enter in its minutes an order declaring that the district of the name, and with the boundaries theretofore established (setting forth the boundaries), has been duly created, and shall declare the person receiving the highest number of votes for member of the commission, duly elected.

The order shall be conclusive evidence of the fact and of the regularity of all prior proceedings provided for by this part, and of the existence of, and the validity of the creation of, the district.