Below are the different types of home dwellings as defined in Arlington County’s Zoning Ordinance (ACZO).
One-Family Detached Dwelling
A residential building containing one dwelling unit designed for one family and located on a single lot with required yards on all four sides. (e.g. single-family home)
A residential building with two attached dwelling units located on two lots that share a common wall along the lot line and where each dwelling unit has its own external entrance. (e.g., side-by-side two dwelling unit building)
Two attached dwelling units in a single structure on a single lot with dwelling units situated either wholly or partially over or under the other dwelling unit. The building has all exterior characteristics of a one-family attached dwelling, having a single front entrance or one front and one side entrance on the first floor; provided an outside, enclosed stairway located parallel and abutting the rear of the dwelling shall be permitted for direct access to the second floor level. (e.g., “over-under” two dwelling unit building)
One of a series of three or more attached similar dwelling units, located on separately-owned lots or on a single lot, separated by common party walls without openings extending from basement to roof, and where each unit has its own external entrance.
A building or portion thereof, designed for occupancy by three or more families living independently of each other. (e.g., condominiums, apartment buildings, garden-style apartment houses, etc.)
NOTE: The Virginia Uniform Statewide Building Code (VUSBC) requires more stringent regulations for multifamily buildings (apartments and condominiums) which provide accommodations for transient lodgers than for single-family dwellings. Typically, multifamily residential buildings hosting transient lodgers require a certificate of occupancy for the entire building.