Hallways, stairways, and other common space used in common by the occupants of more than one habitation shall have adequate lighting facilities, which shall be kept in good condition at all times.
The artificial illumination of stairs and hallways in each housing business licensed under this subtitle shall be arranged and maintained to provide illumination from sunset to sunrise and at other times when daylight does not provide illumination of an intensity of at least six-foot candles (6 ft.) at the tread and floor level.
D.C. Mun. Regs. tit. 14, r. 14-505