The source of these data is the U.S. Census Bureau's Residential Construction Branch. The statistics are based upon reports submitted by local building permit officials in response to a mail survey. They are obtained using Form C-404, "Report of New Privately-Owned Residential Building or Zoning Permits Issued." When a report is not received, missing data is either (1) obtained from the Survey of Use of Permits (SUP) which is used to collect information on housing starts, or (2) imputed. Data for SUP are available only for about 850 places for which Census Bureau field representatives list permits. Imputations are based on the assumption that the ratio of current month authorizations to those of a year ago should be the same for reporting and nonreporting places.



1. Dwelling unit (or housing unit): A house or apartment unit intended for occupancy as separate living quarters and having either:

a. a kitchen or cooking facilities,


b. direct access from the outside through a common hall.

Group living quarters, such as dormitories, nursing homes, and barracks are included.

2. Single-family house: A house with one dwelling unit includes semi-detached and row houses if the units are separated by a ground to roof party wall. Does not include mobile homes.

3. Two-family house: A house with two dwelling units. If built side-by-side, they do not have a ground to roof party wall and they generally have a common attic, basement, heating plant, and other common features.

4. Three-and four-family buildings: Each building contains three or four housing units having a common basement, heating plant, stairs, water supply and disposal facilities, or entrance.

5. Five-or-more-family buildings: Each building contains five-or-more housing units having a common basement, heating plant, stairs, water supply and sewerage disposal facilities, or entrance. Condominiums and cooperatively owned apartment buildings may fall into this category.

For additional information, call the Census Bureau's Residential Construction Branch on (301) 457-1321.