Before enacting or amending any zoning regulations or maps, the governing authority or the planning commission, if authorized by the governing authority, shall hold a public hearing thereon, which shall be advertised and conducted according to lawfully prescribed procedures. If no established procedures exist, then at least fifteen days' notice of the time and place of such public hearing shall be given in a newspaper of general circulation in the municipality or county. No change in or departure from the text or maps as certified by the local planning commission shall be made pursuant to such hearing unless such change or departure be first submitted to the planning commission for review and recommendation. The planning commission shall have thirty days within which to submit its report to the governing authority. If the planning commission fails to submit a report within the thirty-day period, it shall be deemed to have approved the change or departure. When the required public hearing is held by the planning commission, no public hearing by the governing authority shall be required before amending the zoning ordinance or resolution or maps.

No challenge to the adequacy of notice or challenge to the validity of a regulation or map, or amendment thereto, whether enacted before or after the effective date of this section because of inadequacy of notice, shall be made more than two years after the public hearing, if there has been substantial compliance with the notice requirements of this section or with established procedures of the governing authority or the planning commission.