Whenever in the opinion of the board of county commissioners it becomes necessary to construct a water main within the boundaries of a municipal corporation for the service of one or more sewer districts wholly outside of such municipal corporation, the board may construct such main in the streets and alleys of such municipal corporation but shall restore all such streets and alleys to their original condition, and the cost thereof shall be a part of the cost of such main. Prior to the preparation of plans for such improvement, such municipal corporation shall be given an opportunity to co-operate in the construction and use of such water main as provided in this section and section 6103.03 of the Revised Code.
R.C. § 6103.26