D.C. Code § 34-911
If upon such investigation the rates, tolls, charges, schedules, or joint rates shall be found to be unjust, unreasonable, insufficient, or unjustly discriminatory, or to be preferential or otherwise in violation of any of the provisions of this subtitle, the Commission shall have power to determine and by order fix and order to be substituted therefor such rate or rates, tolls, charges, or schedules as shall be just and reasonable. If upon such investigation it shall be found that any regulation, time schedule, act, or service complained of is unjust, unreasonable, insufficient, preferential, unjustly discriminatory, or otherwise in violation of any of the provisions of this section, or if it be found that reasonable service is not supplied, the Commission shall have power to determine and substitute therefor such other regulations, time schedules, service, or acts and to make such orders respecting and such changes in such regulations, time schedules, service, or acts as shall be just and reasonable. And upon any investigation for the purpose of determining upon and requiring any reasonable extension or extensions of lines or of service that shall promise to be compensatory within a reasonable time, the Commission shall have power to fix, determine, and require every such extension or extensions to be made and the terms and conditions upon which the same shall be made; provided, that no hearing shall be had and no order shall be made respecting such extension or extensions, without notice to the public utility affected thereby, as provided in § 34-910.
D.C. Code § 34-911