Iowa Code § 275.23: Frequency of change.

A school district which is enlarged, reorganized, or changes its boundaries under sections 275.12 through 275.18, 275.20, and 275.22, shall not file a petition under section 275.12 for the purpose of reducing the area served or changing the boundaries to exclude areas encompassed by the enlargement, reorganization, or boundary changes for a period of five years following the effective date of the enlargement, reorganization, or boundary change unless the action is approved by the director of the department of education.