48 C.F.R. § 22.406-1 – Policy.

(a) General. Contracting agencies are responsible for ensuring the full and impartial enforcement of labor standards in the administration of construction contracts. Contracting agencies shall maintain an effective program that shall include—
1. (1) Ensuring that contractors and subcontractors are informed, before commencement of work, of their obligations under the labor standards clauses of the contract;
2. (2) Adequate payroll reviews, on-site inspections, and employee interviews to determine compliance by the contractor and subcontractors, and prompt initiation of corrective action when required;
3. (3) Prompt investigation and disposition of complaints; and
4. (4) Prompt submission of all reports required by this subpart.
(b) Preconstruction letters and conferences. Before construction begins, the contracting officer shall inform the contractor of the labor standards clauses and wage determination requirements of the contract and of the contractor's and any subcontractor's responsibilities under the contract. Unless it is clear that the contractor is fully aware of the requirements, the contracting officer shall issue an explanatory letter and/or arrange a conference with the contractor promptly after award of the contract.