Ohio Rev. Code § 4909.07
The public utilities commission, during the making of the valuation provided for in sections 4909.04 to 4909.13 of the Revised Code, and after its completion, shall in like manner keep itself informed through its engineers, experts, and other assistants of all extensions, improvements, or other changes in the condition and value of the property of all public utilities or railroads and shall ascertain the value of such extensions, improvements, and changes. The commission shall, as is required for the proper regulation of such public utilities or railroads, revise and correct its valuations of property, showing such revisions and corrections as a whole and as to each county. Such revisions and corrections shall be filed in the same manner as original reports.
"Valuation" and "value," as used in this section, may include, with respect to a natural gas, water-works, or sewage disposal system company, projected valuation and value as of the date certain, if applicable because of a future date certain under section 4909.15 of the Revised Code.
R.C. § 4909.07