Data collected during a 2014 survey allow NAHB to produce, for the first time, summary statistics that describe the typical residential subdivision being built in the United States. The results were recently published as a Special Study in HousingEconomics.com.
For subdivisions of single-family detached homes, the summary statistics are as follows:
- Median size: 22 acres.
- Median number of housing units: 48.
- Median gross density: 2.1 units per acre.
- 4% include retail space.
- 4% include other (non-retail) commercial space.
The data come from a survey sent electronically to 2,042 NAHB land developers. A total of 266 developers responded (a 13 percent response rate). Eighty-eight of them provided information on one of their development projects, 56 provided information on two projects, and 111 provided information on three projects. So in all the sample contains data on 533 development projects, the vast majority of which meet a commonly used criterion for residential subdivision (at least four housing units).
Not surprisingly, the typical characteristics vary quite a bit depending on the type of subdivision. The chart below shows how the number of housing units per subdivision varies across six basic types.
To establish consistent woking concept of metropolitan area, the survey provided a brief summary of the official Office of Management and Budget definition: a densely settled urban area and surrounding counties tied to the urban area by frequent commuting. In terms of number of housing units, subdivisions inside and outside of metropolitan areas are quite similar. The median number of housing units in subdivisions built inside metro areas is 59, and the median outside is 63.
The survey also collected information on the type of housing built in the subdivision: single-family detached, townhomes, multifamily or some mix of these types. The “mixed” subdivisions contain every possible combination of housing types–including all three in the same subdivision–and tend to be relatively large. The median in mixed subdivisions is 291 housing units, compared to 48 in single-family-only, 56 in townhome-only, and 86 in multifamily-only subdivisions.
For additional details, including a separate profile for each of the six basic subdivision types, consult the full study, available free to everyone on NAHB’s web site.