The Ohio water development authority shall not issue any bonds or otherwise participate in any project authorized by this chapter or Chapter 6123 of the Revised Code unless the contract, resolution, or other written document setting forth the board’s participation specifies that all wages paid to laborers and mechanics employed on the projects shall be paid at the prevailing rates of wages of laborers and mechanics for the class of work called for by the project, which wages shall be determined in accordance with the requirements of Chapter 4115 of the Revised Code for determination of prevailing wage rates, provided that the requirements of this section do not apply to loans made to boards of county commissioners under division (V) of section 6121.04 of the Revised Code or where the federal government or any of its agencies furnishes by loan or grant all or any part of the funds used in connection with the project and prescribes predetermined minimum wages to be paid to the laborers and mechanics, and provided that if a non-public user beneficiary of the project undertakes, as part of the project, construction to be performed by its regular bargaining unit employees who are covered under a collective bargaining agreement that was in existence prior to the date of the commitment instrument setting forth the board’s participation, the rate of pay provided under the collective bargaining agreement may be paid to those employees.