Iowa Code § 26.12: When hearing necessary.

If the estimated total cost of a public improvement exceeds the competitive bid threshold in section 26.3, or as adjusted in section 314.1B, the governmental entity shall not enter into a contract for the public improvement until the governmental entity has held a public hearing and has approved the proposed plans, specifications, and form of contract, and estimated total cost of the public improvement. Notice of the hearing must be published as provided in section 362.3 and shall include a description of the public improvement and its location. At the hearing, any interested person may appear and file objections to the proposed plans, specifications, contract, or estimated cost of the public improvement. After hearing objections, the governmental entity shall by resolution enter its decision on the plans, specifications, contract, and estimated cost. This section does not apply to the state.