29 C.F.R. § 4.161
The standards established pursuant to the Act for minimum monetary wages to be paid by contractors and subcontractors under service contracts in excess of $2,500 to service employees engaged in performance of the contract or subcontract are required to be specified in the contract and in all subcontracts (see § 4.6 ). Pursuant to the statutory scheme provided by sections 2(a)(1) and 4(c) of the Act, every covered contract (and any bid specification therefor) which is in excess of $2,500 shall contain a provision specifying the minimum monetary wages to be paid the various classes of service employees engaged in the performance of the contract or any subcontract thereunder, as determined by the Secretary or his authorized representative in accordance with prevailing rates for such employees in the locality, or, where a collective bargaining agreement applied to the employees of a predecessor contractor in the same locality, in accordance with the rates for such employees provided for in such agreement, including prospective wage increases as provided in such agreement as a result of arm's-length negotiations. In no case may such wages be lower than the minimum wage specified under section 6(a)(1) of the Fair Labor Standards Act of 1938, as amended. (For a detailed discussion of the application of section 4(c) of the Act, see § 4.163 .) If some or all of the determined wages in a contract fall below the level of the Fair Labor Standards Act minimum by reason of a change in that rate by amendment of the law, these rates become obsolete and the employer is obligated under section 2(b)(1) of the Service Contract Act to pay the minimum wage rate established by the amendment as of the date it becomes effective. A change in the Fair Labor Standards Act minimum by operation of law would also have the same effect on advertised specifications or negotiations for covered service contracts, i.e., it would make ineffective and would supplant any lower rate or rates included in such specifications or negotiations whether or not determined. However, unless affected by such a change in the Fair Labor Standards Act minimum wage, by contract changes necessitating the insertion of new wage provisions (see §§ 4.5(c) and 4.143-4 .145) or by the requirements of section 4(c) of the Act (see § 4.163 ), the minimum monetary wage rate specified in the contract for each of the classes of service employees for which wage determinations have been made under section 2(a)(1) will continue to apply throughout the period of contract performance. No change in the obligation of the contractor or subcontractor with respect to minimum monetary wages will result from the mere fact that higher or lower wage rates may be determined to be prevailing for such employees in the locality after the award and before completion of the contract. Such wage determinations are effective for contracts not yet awarded, as provided in § 4.5(a) .
29 C.F.R. §4.161