Except as provided elsewhere in this title, the minimum required rear yard shall be as set forth in this section.
The minimum depth of the rear yard shall be two and one-half inches (2.5 in.) per one foot (1 ft.) 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 twelve feet (12 ft.).
Except as required in Subtitle J § 207.5, the rear yard need not be provided below a horizontal plane twenty feet (20 ft.) above the mean finished grade at the middle of the rear of the structure.
For that portion of the structure above the horizontal plane, the depth of rear yard may be measured as follows:
Where the rear lot line of a lot abuts or is separated only by an alley from a residential zone as defined by Subtitle A § 101.9 or residential use of a property, a rear yard shall be provided from the ground up, subject to the transition setback requirements of Subtitle J § 210.
A required rear yard may be within a required transition setback provided all transitional setback conditions are met.
D.C. Mun. Regs. tit. 11, r. 11-J207