When the governing body shall determine that such rules and regulations are necessary in any area or section of the county lying outside of the limits of incorporated municipalities, it shall hold a public hearing, after notice thereof, describing the area or section, shall have been published in a newspaper of general circulation in the county at least once a week for three successive weeks, for the purpose of considering the necessity of such rules and regulations, the type, coverage and contents thereof, and the exact extent of the area or section proposed to be covered thereby, at which hearing any and all interested parties shall be entitled to appear and be heard. After such hearing shall have been had, and not before, the governing body may provide and prescribe by resolution or ordinance the rules and regulations applicable in and to such area or section.