Except such resolutions or ordinances as may be necessary for the immediate preservation of the public peace, health, or safety, or support of the municipal government and its existing public institutions, or which provide for an election or for hearing on an improvement or assessment or which call for bids, which take effect upon the passage and publication thereof, every resolution or ordinance passed by the governing body shall take effect on the twentieth day after its publication unless suspended by operation of a referendum.
SDCL 9-19-13