Ohio Rev. Code § 713.25
The planning commission of any municipal corporation to which a regional or county plan is certified under section 713.24 of the Revised Code, may adopt such plan, and it shall thereupon have the same force within such municipal corporation as is provided by law or charter for plans prepared and adopted by the local planning commission. The board of county commissioners may adopt such plan so far as it relates to nonmunicipal territory. Thereafter no public building, roadway, bridge, viaduct, or other public improvement or utility, publicly or privated owned, whose construction or location would constitute a departure from the plan, shall be constructed or authorized by the board except by unanimous vote. Such plans shall not designate the specific lots or parcels of land upon which such system, facilities, buildings, and improvements are proposed to be placed, but only the general site or location thereof. The effect of the adoption of such plan by the board shall cease as regards the location of any sewage or garbage disposal plant, and no official action of the board shall be controlled thereby in such respect, unless the site shown on the plan as the location of such plant is purchased within six months after the adoption of the plan by the board, or unless proceedings for the appropriation of the necessary property are commenced within a period of six months and such property is then or thereafter appropriated in such proceedings.
R.C. §713.25