D.C. Mun. Regs. tit. 14, § 3803
3803.1 All pleadings and other documents required to be served upon any party under this chapter shall be served upon that party or shall be served upon the representative designated by that party as provided in § 3812 or by law to receive service of documents.
3803.2 When a party has a representative of record as provided in § 3812, service shall be made upon the representative.
3803.3 Service upon a person shall be completed in accordance with § 904 of the Act.
3803.4 Actual receipt of service shall bar any claim of defective service, except for a claim with respect to the timeliness of service.
3803.5 Service by mail shall be complete upon mailing.
3803.6 Pleadings and other documents shall be served on the other party or parties prior to or at the same time as they are filed with the Commission.
3803.7 Proof of service upon parties shall be provided for all pleadings and other documents, shall be in writing, and 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, 1339 (March 7, 1986).