Ohio Rev. Code Ann. § 6115.191

If a municipal corporation, township, or other member or customer of a sanitary district organized wholly for the purpose of providing a water supply for domestic, municipal, and public use that includes two municipal corporations in two counties is delinquent in paying any moneys owed to the sanitary district for the supply of water from the district, the board of directors of the sanitary district may assess interest on the unpaid balance that reflects administrative and financial costs incurred by the sanitary district as a result of the delinquency.