A house, apartment, mobile home or trailer, group of rooms, or single room occupied as a separate living quarter or, if vacant, intended for occupancy as a separate living quarter. Separate living quarters are those in which the occupants live and eat separately from any other persons in the building and which have direct access from the outside of the building or through a common hall.
The occupants may be a single family, one person living alone, two or more families living together, or any other group of related or unrelated persons who share living arrangements (except as described in definition of Group Quarters, Persons In). For vacant units, the criteria of separateness and direct access are applied to the intended occupants whenever possible. If that information cannot be obtained, the criteria are applied to the previous occupants. Both occupied and vacant housing units are included in the housing unit inventory, except that recreational vehicles, boats, caves, tents, railroad cars, and the like are included only if they are occupied.
The first Census of Housing in 1940 established the "dwelling unit" concept. Although the term became "housing unit" and the definition has been modified slightly in each succeeding census, the 1980 definition is essentially comparable to previous censuses. In 1970, the definition of a housing unit stipulated the occupants to live and eat separately and to have either direct access or complete kitchen facilities. For 1980 direct access is required; the alternative of complete kitchen facilities has been dropped. In 1970 vacant mobile homes were not counted. In 1980 vacant mobile homes are included in the housing inventory if they are intended for occupancy where they stand. Also in 1970 units with 6 or more unrelated persons living together were classified as group quarters; for 1980 that requirement was raised to 10 or more unrelated persons.
See also: "Occupancy Status;" "Tenure;" "Units at Address;" "Units in Structure;" "Year-Round Housing Units."