Ohio Rev. Code Ann. § 6117.021

At any time after the formation of a county sewer district, the board of county commissioners may enter into a contract, on terms and for the period of time that are mutually agreed on, with any other public agency under which the public agency will conduct projects and activities for the purpose of complying with the requirements of phase II of the storm water program of the national pollutant discharge elimination system established in 40 C.F.R. part 122.