A public water system that considers commencing or discontinuing fluoridation of its water supply on a continuing basis shall notify its customers and the department of its intentions at least 90 days prior to a vote or decision on the matter. The water system shall notify its customers via radio, television, newspaper, regular mail, electronic means, or any notification methods which effectively notify customers at least 90 days prior to any meeting at which the vote or decision will occur. Any public water system that violates the notification requirements of this subsection [section] shall return the fluoridation of its water supply to its previous level until proper notification is provided under the provisions of this section.