D.C. Mun. Regs. tit. 18, r. 18-1022
Depositions may be taken and submitted on written interrogatories in substantially the same manner as oral depositions and shall be permitted under similar circumstances by the examiner. Two (2) copies shall be served on each party.
Within seven (7) days after service any party may file with the examiner his or her objections, if any, to the interrogatories and may file such cross-interrogatories as he or she desires to submit.
Cross-interrogatories shall be served in the same manner on each party as are interrogatories. Two (2) copies together with a copy of any objections to interrogatories shall be served on each party who shall have five (5) days thereafter to file and serve his objections.
Objections to interrogatories or cross-interrogatories shall be decided by the examiner.
Objections to interrogatories or cross-interrogatories shall be made before the order for taking the deposition issues, and if not so made shall be deemed waived.
The provisions of §§ 1021.9 through 1021.11 shall be applicable to written interrogatories.
Interrogatories shall conform to the specifications of §§ 1010 through 1012.
The fact that interrogatories are filed in a proceeding as provided in this section does not constitute a determination that they are admissible in evidence or that they may be used in the proceeding.
Only those parts or the whole of interrogatories received in evidence at a hearing shall constitute a part of the record in the proceeding upon which a decision is based.
D.C. Mun. Regs. tit. 18, r. 18-1022