Ohio Rev. Code § 4909.10
For the purpose of ascertaining the value of the property of any public utility or railroad in this state, including municipally owned or operated public utilities, the public utilities commission may cause a hearing to be held at such time and place as the commission designates. Before any hearing is had, the commission shall give the public utility or railroad affected thereby, and if a substantial portion of said public utility or railroad is situated in any municipal corporation, then to the mayor of such municipal corporation, at least thirty days' written notice specifying the time and place of hearing and give such further notice by publication or otherwise as it deems necessary to apprise the public of the time and place of hearing. This section does not prevent the commission from making any preliminary examination or investigation into the matters referred to in this section, or from inquiring into such matters in any other investigation or hearing. All public utilities or railroads affected, and any municipal corporation in which the whole or the major portion of said public utility or railroad is located, are entitled to be heard and to introduce evidence at such hearing. The commission may resort to any other source of information available. The evidence introduced at such hearing shall be reduced to writing and certified under the seal of the commission.
R.C. § 4909.10