D.C. Mun. Regs. tit. 14, § 1401
1401.1 Except as provided in the District of Columbia Zoning Regulations, 11 DCMR § 3203, no person shall use any structure, land, or part thereof for any purpose other than a one-family dwelling until a Certificate of Occupancy has been issued to that person stating that the use complies with the Zoning Regulations and related building, electrical, plumbing, mechanical and fire prevention requirements.
SOURCE: Notice of Final Rulemaking published at 29 DCR 5571-72 (December 17, 1982).