Whenever the municipality determines that an emergency exists, in that the water supply available to the entire municipality for essential functions is in jeopardy because of drought, flood, natural disaster, other act of God, or any other cause beyond the control of the municipality, the municipality may impose such restrictions on the use of water as it determines to be necessary to meet such emergency. In the event the municipality declares such an emergency and imposes restrictions on the use of water, all users of the municipality's water shall submit to those restrictions.