D.C. Mun. Regs. tit. 19, § 2052
2052.1 In computing any period of time specified in this chapter, the day of the act, event, or default is not be counted, and the last day of the period is counted unless it is a Saturday, Sunday, legal holiday, or day on which the Department is officially closed, in which event the time period continues until the next day that is not a Saturday, Sunday, legal holiday, or day on which the Department is officially closed.
SOURCE: Final Rulemaking published at 35 DCR 3710, 3728-29 (May 20, 1988).