D.C. Mun. Regs. tit. 14, § 3911
3911.1 All documents required to be served upon any person under this subtitle shall be served upon that person, or shall be served upon the representative designated by that person or by law to receive service of documents.
3911.2 When a party has a representative of record as provided in § 4004, service shall be made upon the representative.
3911.3 Service upon a person shall be completed in accordance with § 904 of the Act.
3911.4 Actual receipt of service shall bar any claim of defective service, except for a claim with respect to the timeliness of service.
3911.5 Service by mail shall be complete upon mailing.
3911.6 Pleadings and other documents shall be served on the other parties prior to or at the same time as filed with the hearing examiner.
3911.7 Proof of service of pleadings and other documents to parties shall meet the following requirements:
(a) Be submitted in writing; and
(b) Shall show the date, person served, address at which service was made, and the manner of service.
SOURCE: Notice of Final Rulemaking published at 33 DCR 1336, 1357 (March 7, 1986).