Ohio Rev. Code § 727.24
After the passage of an ordinance under section 727.23 of the Revised Code, to proceed with a public improvement, the improvement may be constructed by force account, or a contract for the construction of the improvement shall be let in the manner provided by law, provided that in the event that the lowest and best bid for labor and materials for the public improvement exceeds the estimated cost for labor and materials as filed under section 727.12 of the Revised Code by fifteen per cent or more, then no contract shall be entered into until the legislative authority determines by a majority vote at a special meeting or its next regular meeting, after public hearing, that the improvement should be made. When the lowest and best bid will so exceed the estimated cost, the clerk of the legislative authority shall publish a notice once in a newspaper of general circulation in the municipal corporation specifying the time and place, not sooner than forty-eight hours following such notice, when owners of property to be assessed for the improvement shall be heard on the question of whether such improvement should be made. In the event that such hearing is to be held at a special meeting, the clerk of the legislative authority shall serve notice on each member of the legislative authority of a special meeting to be held at the time and place set forth in the notice of the hearing and the purpose of the special meeting. Such notice shall be served in the manner provided for the service of notice of special meetings of legislative authority. At the meeting for such hearing, or any adjournment thereof, the legislative authority shall, by a majority vote, determine whether or not the public improvement should be made. If the legislative authority determines that the improvement should be made, the improvement may be constructed by force account or a contract may be let for the construction of such public improvement to the lowest and best bidder.
Notwithstanding the foregoing provisions of this section, in the event that the improvement is being undertaken by the municipal corporation in cooperation with the government of the United States or the state or any department or agency thereof, or any political subdivision of this state, or any one or more of them, and under the statutes or the cooperative contract authorizing such improvement the municipal corporation is required to pay its share of the estimated cost of the improvement to another party to such contract prior to the advertising for construction bids, the legislative authority of the municipal corporation may, by majority vote, determine to dispense with any notice, hearing, and determination that might otherwise be required by this section prior to the entry into a construction contract; provided that, if after the actual cost of such improvement has been ascertained, the cost to the municipal corporation for labor and materials exceeds the estimated cost therefor as filed under section 727.12 of the Revised Code by fifteen per cent or more, then the assessments levied under section 727.25 of the Revised Code shall not exceed in the aggregate the estimated assessment adopted under section 727.23 of the Revised Code unless the legislative authority, by majority vote, determines that this shall be done after notice and hearing in the manner provided in this section.
No subsequent change in the cost of the improvement shall affect the validity of the assessment proceedings taken under Chapter 727. of the Revised Code if the applicable provisions of this section have been complied with.
R.C. §727.24