Ohio Rev. Code § 6119.23
Before or after the construction of all or a part of the sewers provided for by a plan of sewerage devised in accordance with section 6119.19 of the Revised Code, the board of trustees of the regional water and sewer district may amend such plan by providing for such intercepting sewers, without regard to sewer districts, as are necessary to furnish an additional outlet for the system so adopted, and to provide for the construction thereof as provided in sections 6119.01 to 6119.42, inclusive, of the Revised Code, and apportion the cost and expense thereof equitably among the districts directly or indirectly sewered, in whole or in part thereby, or assess and collect the amount apportioned to each district, or the board may apportion a part only of such cost and expense among the districts directly or indirectly sewered, in whole or in part thereby, and provide for the payment of the residue thereof by the district. The board may also amend such plan by making new sewer districts, by subdividing districts already established, giving a name and number thereto, or provide for the construction of the main and branch sewers therein, and may assess the cost and expense thereof upon the lots and lands within the area or district according to benefits.
R.C. § 6119.23