Iowa Code § 468.211: Assessment of benefits.

Appointment of commissioners to assess benefits and classify lands within the district and all proceedings relative to such assessment and classification shall be as otherwise provided in this subchapter, parts 1 through 5, except that when the lands of the district have previously been classified, the commissioners shall classify and assess only such lands as have been added to the district by adoption of the plan and recommend such changes in existing classifications as are materially affected by the plan so adopted. The board may, upon hearing, adjust the classification of lands affected by the plan.