D.C. Mun. Regs. tit. 26, r. 26-B315
From the start of the proceeding until the rendering of a final decision, no person may communicate ex parte with the Commissioner, or designated hearing officer, regarding the merits of the proceeding.
The Commissioner shall not be prohibited from communicating with officials of the District government and members of the Department not representing the Department in the proceeding on policy and procedural matters during the course of a proceeding before the Commissioner.
The Commissioner shall not be prohibited from communicating with any party that is a regulated entity or person of the Department on matters not related to the merits of a matter before the Commissioner.
If the Commissioner determines that a person has violated the prohibition on ex parte communications, he or she may impose appropriate sanctions against that person, which may include excluding the person from the proceeding or deciding against it with prejudice.
As used in this section, the term "ex parte" shall mean any oral or written communication related to the merits of a pending matter made to the Commissioner, not in the public hearing record, with respect to which reasonable prior notice to all parties to the proceeding is not given. An inquiry about the status of a proceeding is not considered an ex parte communication.
D.C. Mun. Regs. tit. 26, r. 26-B315