Iowa Code § 335.6
The board of supervisors shall provide for the manner in which the regulations and restrictions and the boundaries of the districts shall be determined, established, and enforced, and from time to time amended, supplemented, or changed. However, the regulation, restriction, or boundary shall not become effective until after a public hearing, at which parties in interest and citizens shall have an opportunity to be heard. Notice of the time and place of the hearing shall be published as provided in section 331.305. The notice shall state the location of the district affected by naming the township and section, and the boundaries of the district shall be expressed in terms of streets or roads if possible. The regulation, restriction, or boundary shall be adopted in compliance with section 331.302.
Iowa Code § 335.6
Referred to in §329.9, 335.7, 427B.1, 427B.20, 657.9