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 anyone 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 § 709.
711.6 Voting booths shall provide privacy for the voter while voting.
SOURCE: Final Rulemaking published at 39 D.C. Reg. 2467, 2488 (April 10, 1992); and amended by Final Rulemaking published at 51 D.C. Reg. 7412 (July 30, 2004).