Single-Family Home Share
The share of a tract's housing units that sit in one-unit structures, detached or attached, and its change over time.
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The share of housing units in a tract that sit in one-unit structures.
The Census Bureau collects units in structure at both occupied and vacant housing units. "A structure is a separate building that either has open spaces on all sides or is separated from other structures by dividing walls that extend from ground to roof," and the published counts are "for the number of housing units in structures of specified type and size, not for the number of residential buildings" (ACS Subject Definitions).
Two one-unit categories are counted here. A 1-unit detached structure is "detached from any other house, that is, with open space on all four sides," and remains detached "even if [it has] an adjoining shed or garage." A 1-unit attached structure "has one or more walls extending from ground to roof separating it from adjoining structures"; the Bureau notes that "in row houses (sometimes called townhouses), double houses, or houses attached to nonresidential structures, each house is a separate, attached structure if the dividing or common wall goes from ground to roof."
Both are included, so row houses and townhouses count as single-family. Mobile homes do not.
The denominator is all housing units in the tract, occupied and vacant alike.
Metrics in this family#
Considerations#
This measure counts structures, not tenure or ownership. A large share of single-family houses in the United States are rented, and the share here says nothing about who occupies them. For that, see homeownership rate.
Two-unit buildings and mobile homes fall outside both this measure and the multifamily share, so the two do not add to one.
The share moves when units are added or removed, and also when a tract's total stock grows around an unchanged number of houses. A falling share is not evidence that houses were lost.
ACS 5-year windows overlap. Each vintage shares four of its five years with the vintage before it, so year-over-year movement reflects smoothed rolling estimates rather than independent annual readings. The 5-year and 10-year trends compare vintages whose windows do not overlap; the 3-year trend compares vintages sharing two years and is damped.
Census tract boundaries were redrawn for the 2020 census. Estimates published on earlier boundaries are carried onto current ones before use — see geography.
In tracts with few housing units the estimate rests on a small sample and carries a wide margin of error.
References#
- 1ACS Subject Definitionshttps://www2.census.gov/programs-surveys/acs/tech_docs/subject_definitions/2024_ACSSubjectDefinitions.pdf