D.C. Mun. Regs. tit. 11, r. 11-404
A rear yard shall be provided for each structure located in a Residence District, the minimum depth of which shall be as set forth in the following table:
ZONE DISTRICT | MINIMUM DEPTH OF REAR YARD |
R-1-A, R-1-B R-2, R-3, R-4, R-5-A R-5-B, R-5-C, R-5-D R-5-E | 25 feet 20 feet 4 inches per foot of vertical distance from the mean finished grade at the middle of the rear of the structure to the highest point of the main roof or parapet wall, but not less than 15 feet. 3 inches per foot of vertical distance from the mean finished grade at the middle of the rear of the structure to the highest point of the main roof or parapet wall, but not less than 12 feet. |
In the case of a through lot or a corner lot abutting three (3) or more streets, the depth of rear yard may be measured from the center line of the street abutting the lot at the rear of the structure.
In the case of a lot proposed to be used by a public library, public school or a public recreation and community center that abuts or adjoins along the rear lot line a public open space, recreation area, or reservation, the required rear yard may be reduced or omitted.
In the case of a building existing on or before May 12, 1958, an extension or addition may be made to the building into the required rear yard; provided, that the extension or addition shall be limited to that portion of the rear yard included in the building area on May 12, 1958.
D.C. Mun. Regs. tit. 11, r. 11-404