D.C. Mun. Regs. tit. 26-A, § 1905
1905.1 Any notice required by this chapter may be served either personally, by certified mail or return receipt requested, directed to the applicant or certification holder at the last known address as shown by the records of the Department of Consumer and Regulatory Affairs.
SOURCE: Final Rulemaking published at 36 DCR 4922 (July 14, 1989).