D.C. Mun. Regs. tit. 18, r. 18-1013
Formal notices, final orders, and similar documents issued by the Hearing Division will be served by the Division on all parties to the proceedings.
Any document filed by any party with the Hearing Division or an Examiner shall be served upon all parties to the proceedings in which it is filed.
Service may be made by regular mail, by registered or certified mail, or by personal delivery.
Service upon a party may be upon an individual, or upon a partnership member, or upon the president or other officer of the corporation, company, firm, or association to be served, or upon the assignee or legal successor of any of the foregoing, or upon any attorney of record for the party, or upon the agent designated by a party to receive service of documents in a particular proceeding as provided by District of Columbia law other than the District of Columbia Administrative Procedure Act.
Service by regular or registered or certified mail shall be made at the address of the party designated under § 1012.4 to receive service of documents. If no such person is designated, service may be made at the usual residence or principal place of business of the party, or, if unknown, at the last address furnished by the party to the Department.
Proof of service shall accompany all documents when they are tendered for filing. Proof of service of any document shall consist of one of the following:
Acknowledgement of service may be made by any person at the address shown on the document who is sixteen (16) years of age or over.
Whenever proof of service is made, the date of mailing shall be the date of service, except that a final order of revocation or suspension shall be considered served as provided specifically in other provisions of this title, or as provided in this section.
D.C. Mun. Regs. tit. 18, r. 18-1013