556.1 The maximum permitted building height, not including the penthouse or rooftop structure, in the D-6 zone shall be as follows:

Street Right-of-Way Width	Maximum Permitted Building Height, Not Including Penthouse or Rooftop Structure
Greater than or equal to 110 ft.	130 feet
Less than 110 ft. but greater than or equal to 100 ft.	120 feet
Less than 100 ft. but greater than or equal to 90 ft.	110 feet
Less than 90 ft.	No taller than the width of the street right of way, plus 20 feet

5560.2 A building on a lot in the D-6 zone fronting on Massachusetts Avenue, N.W. shall conform to the height requirements for the Massachusetts Avenue Corridor and Mount Vernon Square Sub-Area in Subtitle I § 610.

5560.3 The maximum permitted height of a penthouse or rooftop structure shall be twenty feet (20 ft.). The maximum permitted number of stories for penthouse habitable space shall be one (1) plus a mezzanine, except a second story shall be permitted for penthouse mechanical space.

SOURCE: Final Rulemaking published at 63 DCR 2447, 3041 (March 4, 2016 – Part 2); as amended by Final Rulemaking published at 63 DCR 10932 (August 26, 2016); as amended by Final Rulemaking published at 68 DCR 013834 (December 24, 2021).