D.C. Mun. Regs. tit. 11-D, § 208
208.1 Except as provided elsewhere in this title, the minimum side yard requirements shall be as set forth in this section.
208.2 Two (2) side yards, each a minimum of eight feet (8 ft.) in width, shall be provided for all detached buildings.
208.3 In any of the R-2 zones, one (1) side yard, a minimum of eight feet (8 ft.) in width, shall be provided for all semi-detached buildings.
208.4 In any of the R-3 zones, one (1) side yard, a minimum of five feet (5 ft.) in width, shall be provided for all semi-detached buildings.
208.5 No side yards are required for row buildings. An existing detached or semi-detached building shall not be treated as a row building through construction or additions.
208.6 Existing conforming side yards shall not be reduced to a non-conforming width or eliminated.
208.7 In the case of a building with a non-conforming side yard, an extension or addition may be made to the building; provided, that the width of the existing side yard shall not be reduced or eliminated; and provided further, that the width of the side yard adjacent to the extension or addition shall be a minimum of five feet (5 ft.).
208.8 In the case of a lot proposed to be used by a public library or public recreation and community center where a side lot line abuts or adjoins a public open space, recreation area, or reservation, no side yard shall be required.
SOURCE: Final Rulemaking published at 67 DCR 13346 (November 13, 2020); as amended by Errata Notice published at 68 DCR 405 (January 8, 2021); as amended by Final Rulemaking published at 70 DCR 011297 (August 25, 2023).