D.C. Mun. Regs. tit. 3, § 711
711.1 Except as provided in this chapter, a voter shall enter a voting booth alone to mark his or her ballot.
711.2 A voter may take sample ballots and any other materials as he or she may desire into the voting booth.
711.3 No voter shall go into a booth that is already occupied, nor shall a voter, poll watcher, election observer, or polling place official communicate with or disturb the occupant of any booth.
711.4 Each voter shall mark the ballot promptly and shall leave the booth.
711.5 No person may occupy a voting booth except for the purpose of voting or for the purpose of rendering assistance to a voter, pursuant to the D.C. Election Act and the provisions of § 710.
711.6 Voting booths shall provide privacy for the voter while voting.
SOURCE: Final Rulemaking published at 39 DCR 2467, 2480 (April 10, 1992); as amended by Final Rulemaking published at 51 DCR 7403 (July 30, 2004); as amended by Final Rulemaking published at 56 DCR 5753-55 (July 17, 2009); as amended by Final Rulemaking published at 57 DCR 4245, 4248 (May 14, 2010); as amended by Final Rulemaking published at 62 DCR 14744 (November 13, 2015).