D.C. Mun. Regs. tit. 24 § 209
If the surface space is to be used for the parking of vehicles, either at a sales lot, a parking lot, a garage, a gasoline filling station, or other business property, the provisions of this section shall apply in addition to the other requirements of this chapter.
The vehicle parking area shall be paved to Department specifications.
Limits of the surface space to be used shall be delineated in accordance with Department specifications and requirements.
Vehicles shall not encroach beyond the marked limits in any manner, including the car or other overhang.
When the operator of a parking facility does not wish to rent surface space adjoining his or her establishment, no vehicle or other object shall encroach beyond the property line in any manner, including car or other overhang, and provisions to prevent an encroachment shall be made as provided in § 606 of this title.
D.C. Mun. Regs. Tit. 24, § 209