Iowa Code § 303.56: Rules.

The board of adjustment shall adopt rules in accordance with any regulation or ordinance adopted by the board of trustees pursuant to this chapter. Meetings of the board of adjustment shall be held at the call of the chairperson and at other times as the board determines. The chairperson, or the acting chairperson, may administer oaths and compel the attendance of witnesses. All meetings of the board shall be open to the public. The board shall keep minutes of its proceedings, showing the vote of each member upon each question, or if absent or failing to vote, indicating that fact, and shall keep records of its examinations and other official actions, all of which shall be immediately filed in the office of the board and shall be a public record.