In computing any period of time specified in this chapter, the day of the act, event, or default shall not be counted, and the last day of the period shall be counted unless it is not a business day, in which event the time period shall continue until the next business day. When the period of time prescribed or allowed is less than 11 days, intermediate Saturdays, Sundays, and legal holidays shall be excluded in the computation.
Where the Department or a respondent to an action pursuant to this chapter has the right or is required to perform some act within a specified period of time, and that act is completed by mail, three (3) days shall be added to the prescribed period.
D.C. Mun. Regs. tit. 27, r. 27-818