Accessory buildings may be permitted within a D zone provided the accessory building is located on the same lot as a principal building; is subordinate to and secondary in size to the principal building, and complies with setback requirements for the zone in which the accessory building is located.
An accessory building shall be used for purposes which are incidental to the use of the principal building.
D.C. Mun. Regs. tit. 11, r. 11-I209