(a) The commissioners courts shall establish procedures for adopting and enforcing zoning regulations and zoning district boundaries. A regulation or boundary is not effective until after a public hearing on the matter at which parties in interest and citizens have an opportunity to be heard. Before the 15th day before the date of the hearing, notice of the time and place of the hearing must be published in a newspaper of general circulation in the county.
(b) If a proposed change to a regulation or boundary is protested in accordance with this subsection, the proposed change must receive, in order to take effect, the affirmative vote of at least three-fourths of all members of the commissioners court. The protest must be written and signed by the owners of at least 20 percent of either:
(1) the area of the lots covered by the proposed change; or
(2) the lots immediately adjacent to the rear of the lots covered by the proposed change and extending 200 feet from those lots, or from the street frontage of the opposite lots.