Section 3-21-6 - Zoning; mode of determining regulations, restrictions and boundaries of district; public hearing required; noticeA. The zoning authority within its jurisdiction shall provide by ordinance for the manner in which zoning regulations, restrictions and the boundaries of districts are: (1) determined, established and enforced; and (2) amended, supplemented or repealed. B. No zoning regulation, restriction or boundary shall become effective, amended, supplemented or repealed until after a public hearing at which all parties in interest and citizens shall have an opportunity to be heard. Notice of the time and place of the public hearing shall be published, at least fifteen days prior to the date of the hearing, within its respective jurisdiction. Whenever a change in zoning is proposed for an area of one block or less, notice of the public hearing shall be mailed by certified mail, return receipt requested, to the owners, as shown by the records of the county treasurer, of lots of land within the area proposed to be changed by a zoning regulation and within one hundred feet, excluding public right-of-way, of the area proposed to be changed by zoning regulation. Whenever a change in zoning is proposed for an area of more than one block, notice of the public hearing shall be mailed by first class mail to the owners, as shown by the records of the county treasurer, of lots or [of] land within the area proposed to be changed by a zoning regulation and within one hundred feet, excluding public right-of-way, of the area proposed to be changed by zoning regulation. If the notice by first class mail to the owner is returned undelivered, the zoning authority shall attempt to discover the owner's most recent address and shall remit the notice by certified mail, return receipt requested, to that address. C. If the owners of twenty percent or more of the area of the lots and [of] land included in the area proposed to be changed by a zoning regulation or within one hundred feet, excluding public right-of-way, of the area proposed to be changed by a zoning regulation, protest in writing the proposed change in the zoning regulation, the proposed change in zoning shall not become effective unless the change is approved by a majority vote of all the members of the governing body of the municipality or by a two-thirds vote of all the members of the board of county commissioners. 1953 Comp., § 14-20-4, enacted by Laws 1965, ch. 300; 1979, ch. 319, § 1; 1981, ch. 91, § 1.