The computation of any period of time prescribed or allowed by this Chapter, by notice, order, rule or regulation to DC Water, or by statute, shall not include the day of the act, event, bill, notice or default.
The last day of the period so computed shall be included unless it is a Saturday, Sunday, or legal holiday, in which event the period runs until midnight of the next day which is not a Saturday, Sunday, or legal holiday.
Whenever a party is required to serve papers or do some act within a prescribed period, and does so by mail, three (3) days shall be added to the prescribed period.
Days as used in this chapter shall refer to calendar days unless otherwise specified.
D.C. Mun. Regs. tit. 21, r. 21-411