(a) Except an ordinance granting a franchise, the following ordinances shall take effect immediately:
(1) Those calling or otherwise relating to an election.
(2) Those specifically required by law to take immediate effect.
(3) Those fixing the amount of money to be raised by taxation or the rate of taxes to be levied.
(4) Those for the immediate preservation of the public peace, health, or safety. The ordinances referred to in this subdivision shall contain a declaration of the facts constituting the necessity and shall be passed by a four-fifths vote of the board of supervisors.
(b) All other ordinances, including ordinances granting a franchise, shall become effective 30 days from and after the date of final passage.