Ohio Rev. Code § 1710.09
Except as otherwise provided in section 1710.10 of the Revised Code, a special improvement district may contract with any person, community improvement corporation, political subdivision as defined in division (F) of section 2744.01, or state agency as defined in section 1.60 of the Revised Code to develop, manage, or implement part or all of any plan adopted under section 1710.06 or division (F) of section 1710.02 of the Revised Code. Before contracting to implement the plan, the district shall permit any member of the district whose property may be assessed for the costs of any improvements or services under the plan to provide for that portion of the improvement or service that is on that member's property at a cost to the district no greater than what the district determines to be the lowest cost allocable to the improvement or service to be performed on that property. However, the board of directors may reject a member's proposed provision of the improvement or service if it would increase the plan's total cost to the district. Members that choose to provide for that portion of the improvement or service that is performed on their property under this division are subject to the same minimum performance specifications required by the district for the rest of the improvement or service, and their property remains subject to the assessment for the plan.
R.C. §1710.09