D.C. Mun. Regs. tit. 31, r. 31-340
Depositions may be taken and submitted on written interrogatories in substantially the same manner as oral depositions as described in § 338 and shall be permitted under similar circumstances by the Chairperson. One (1) copy shall be served on each party.
Within seven (7) days after service, any party may file with the Chairperson 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. One (1) copy 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 or her objections.
Objections to interrogatories or cross-interrogatories shall be decided by the Chairperson.
Objections to interrogatories or cross-interrogatories shall be made before the order for taking and deposition issues, and if not so made shall be deemed waived.
The provisions of §§ 338.9 through 338.11 shall be applicable to written interrogatories.
Interrogatories shall conform to the specifications of §§ 327 through 329.
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. 31, r. 31-340