D.C. Code § 6-401
The Mayor of the District of Columbia is authorized to establish building lines on streets or parts of streets less than 90 feet wide, in the District of Columbia, upon the presentation to him of a plat of the street or part of street upon which such action is desired, showing the lots and the names of the record owners thereof, and accompanied by a petition of the owners of more than one-half of the real estate shown on said plat requesting that building lines be established, or when the Mayor deems that the public interests require that such building lines be established; provided, that no such building lines shall be established on any part of street less than 1 block in length.
D.C. Code § 6-401
Elimination of building restriction line: D.C. Law 7-64, effective January 28, 1988, found the building restriction line in Square 1661 on the west side of 43rd Street, N.W., between Jenifer Street, N.W., and Military Road, N.W., as shown on the surveyor's plat filed under S.O. 86-261, to be unnecessary for street purposes and ordered the restriction eliminated.
Building regulations, powers and duties of Council and Mayor, see § 1-303.04. .