Ohio Rev. Code § 745.09
In the absence of agreement between the municipal corporation and a public utility as to rates, fares, or charges, as provided in section 745.06 of the Revised Code, all rates, fares, tolls, and charges for services rendered and commodities furnished by such public utility shall be sufficient to yield a reasonable compensation to the public utility operating under an indeterminate permit, and in the ascertainment of what shall constitute such reasonable rates, fares, tolls, and charges, the municipal corporation shall have regard, among other things, to the value of all the property of the public utility actually used and useful for the convenience of the public, excluding therefrom the value of any franchise or right to own, operate, or enjoy such property in excess of the amount actually paid to the municipal corporation as the consideration for the grant of such indeterminate permit, exclusive of any value added thereto by reason of a monopoly or merger, and shall have regard to the necessity of making reservation out of the income for surplus, depreciation, and contingencies.
R.C. §745.09