Whenever, after hearing and investigation as provided in this subtitle, the Commission shall find that any rate, toll, charge, regulation, or practice of any public utility within the District of Columbia is unreasonable or discriminatory, it shall have the power to regulate, fix, and determine the same as provided in this subtitle.
D.C. Code § 34-709
Commission rate schedules, amendments, see § 34-602. Rate investigations, see §§ 34-908 et seq. .