Ohio Rev. Code § 5559.05
When the board of county commissioners has determined that any road, street, or alley, or portion thereof shall be improved as provided for in section 5559.02 to 5559.16, inclusive, of the Revised Code, such board shall, by a majority vote, determine the route and termini of such improvement, the kind and extent thereof, and at the same time order the county engineer to make such surveys, plans, profiles, cross sections, estimates, and specifications as are required for such improvement.
Only such storm sewers may be included in plans as are needed solely for the drainage of the street to be improved and of the lots and lands to be specially assessed for the improvement. The board may order the engineer to make alternate surveys, plans, profiles, cross sections, estimates, and specifications, providing therein for different width of roadway, different materials, or other similar variations, and approve any of such alternate surveys, plans, profiles, cross sections, estimates, and specifications.
R.C. §5559.05