D.C. Code § 32-1305 : LOCAL BUSINESS AFFAIRS — LABOR — WAGES AND WORKPLACE FRAUD — PAYMENT AND COLLECTION OF WAGES —1305 - Provisions of law may not be waived
(a) Except as herein provided, no provision of this chapter shall in any way be contravened or set aside by private agreement.
(b) In enforcing the provisions of this chapter, the remuneration promised by an employer to an employee shall be presumed to be at least the amount required by federal law, including federal law requiring the payment of prevailing wages, or by District law.
Applicability of D.C. Law 20-61: Section 11001 of D.C. Law 20-61 provided that, except as otherwise provided, the act shall apply as of October 1, 2013.