D.C. Code § 34-703
It shall be unlawful for any public utility to demand, charge, collect, or receive from any person, firm, or corporation less compensation for any service rendered or to be rendered by said public utility in consideration of the furnishing by said person, firm, or corporation of any part of the facilities incident thereto; provided, that nothing herein shall be construed as prohibiting any public utility from renting any facilities incident to the production, transmission, delivery or furnishing of heat, light, water, or power, or the supply of any liquid, steam, or air, through pipes or tubing, or the conveyance of telegraph or telephone messages, and paying a reasonable rental therefor; or as requiring any public utility to furnish any part of such appliances which are situated in and upon the premises of any consumer or user, except telephone station equipment upon the subscriber's premises, and, unless otherwise ordered by the Commission, meters, and appliances for measurements of any product or service.
D.C. Code § 34-703