D.C. Mun. Regs. tit. 11, § 2811
2811.1 For the purposes of the HE District, the term “preferred uses” shall mean retail, entertainment, cultural, or commercial uses.
2811.2 The following locations are required to devote not less than sixty-five (65) percent of the ground floor frontage to preferred uses and main building entrances, or lobbies to office and residential uses, and shall comply with the design requirements of §§ 2812 through 2814:
(a) The west face of Square F (19th Street frontage);
(b) The northwest corner of Square G;
(c) The southeast corner of Square J at Massachusetts Avenue and Water Street, facing the monumental circle;
(d) The northeast corner of Square M at Massachusetts Avenue and Water Street, facing the monumental circle; and
(e) All Independence Avenue and Massachusetts Avenue frontages;
2811.3 The following locations are permitted to have ground floor preferred uses, provided that the building shall be constructed so that not less than sixty-five (65) percent of the ground floor frontage will be devoted to preferred uses and main building entrances, or lobbies to office and residential uses and shall comply with the design requirements of §§ 2812 through 2814:
(a) All frontages on 19th Street;
(b) All frontages on Burke Street;
(c) The C Street frontage of Square H, facing the park in Square E, for a maximum length of 200 feet from Square H’s northeast corner at the intersection of C Street and 21st Street;
(d) The 21st Street frontage of Square D;
(e) The southeast corner of Square D, which faces the intersection of C Street and Water Street;
(f) The northeast corner of Square I, which faces the intersection of C Street and Water Street; and
(g) All frontages on Water Street.