D.C. Mun. Regs. tit. 1, r. 1-2811
"Service" of a paper or to "serve" a paper means to send or deliver it as set forth in this section.
Every paper filed at OAH shall be served on the other parties or their attorneys or representatives no later than the day it is filed with OAH. Exceptions may be identified in these Rules, by statute, or by OAH order.
Unless otherwise ordered by an Administrative Law Judge or agreed by the parties, service shall be by delivering a copy, mailing a copy, faxing a copy, or sending a copy by commercial carrier.
Service by delivery means:
Service by mail means mailing a properly addressed copy with first-class postage by depositing it with the United States Postal Service.
Service by fax means faxing a legible copy to the correct fax number and receiving confirmation of transmission.
Service by commercial carrier means giving a copy properly addressed to the commercial carrier with the cost of delivery pre-paid for delivery within three (3) calendar days.
Parties may agree, in writing, to other means of service and may withdraw their agreement in writing.
Any paper filed must include a signed statement that the paper was served on the parties. Such a statement is known as a "certificate of service." The certificate of service shall identify the individual serving the paper, the parties served and their addresses, the way it was served, and the date served.
The Clerk may reject, or an Administrative Law Judge may strike, a paper if a party fails to file a certificate of service with the paper.
Actual receipt of a paper shall bar any claim of defective service except for a claim of late service.
D.C. Mun. Regs. tit. 1, r. 1-2811