D.C. Mun. Regs. tit. 15, r. 15-101
A formal or informal complaint, petition or application, may be filed by any person as defined in this chapter.
The Commission, on its own motion or on the petition of any person, at any time, may order a formal investigation or issue an order to show cause.
Orders initiating an investigation or to show cause shall indicate the nature of the matters to be investigated, and shall be served upon the person who is the subject of the order.
The Commission may investigate at any time any matter germane to its jurisdiction.
No fees shall be charged for the commencement of any proceeding or the filing of any pleading or other papers.
Within ten (10) days of the commencement of a proceeding, or the commencement of a proceeding by the Commission on its own motion, any interested party shall file a statement indicating whether the new proceeding should be considered a "rate case" or an "other investigation" for the purposes of D.C. Code § 43-612 (1981 Ed.), and the factual and legal bases for the assertion. Any responsive comments shall be filed within twenty (20) days of the commencement of the proceeding.
For purposes of § 101.6. a proceeding shall be deemed to be commenced upon the occurrence of any of the following events:
D.C. Mun. Regs. tit. 15, r. 15-101