D.C. Mun. Regs. tit. 11, r. 11-C303
All new record lots shall have at least one (1) street lot line on a public street or a public access easement approved by the District Department of Transportation, except that new Alley Record Lots shall instead comply with the rules of Subtitle C § 306.
Where a minimum lot width is required, the length of at least one (1) street lot line shall be at least seventy-five percent (75%) of the required lot width.
Each new lot being created to be used and occupied by a single dwelling unit or flat building, shall have a street frontage measured along the street lot line a distance equal to at least forty percent (40%) of the required minimum width of lot and in no case less than fourteen feet (14 ft.).
Each new lot being created to be used and occupied by an apartment house shall have a street frontage measured along the street line a distance of not less than thirty feet (30 ft.).
D.C. Mun. Regs. tit. 11, r. 11-C303