Ohio Revised Code Title XLIX. Public Utilities § 4926.57

(A) If, pursuant to a complaint filed under section 4926.39 of the Revised Code, a court of common pleas determines that any rate, term, or condition described in the complaint is not just and reasonable, it may do, but is not limited to doing, any of the following:

(B) A refund or payment ordered under this section may not exceed the difference between the actual amount paid under the unjust and unreasonable rate, term, or condition and the amount that would have been paid under the rate, term, or condition established by the court for the period described in the complaint, provided that the period during which refunds or payments are made does not exceed two years.