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Units in Residential Structures

Variable Definitions:

Single Family Units: The percentage of housing structures that contain exactly 1 unit
Multi Family Units: The percentage of housing structures that contain more than 1 unit

American Community Survey (ACS), 5-year estimates, Table B25024 

Years Available*:
2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021

*Note: Each year of available data shown above is a 5-year estimate, or an average of data collected over a five year period. 5-year estimates are used to increase the reliability of the data at small geographies like neighborhoods and census tracts. The years shown on the NDSC map represent the final year of the five year average (e.g. “2010” represents 2006-2010 data, “2011” represents 2007-2011 data, and so on). For the most impactful comparison of data over time, the ACS recommends comparing non-overlapping years (e.g. 2010-14 with 2015-19).

Why are these variables important to measure?

Homes with exactly one unit are known as single-family units. Fully detached, semi-detached, row houses, duplexes, quadruplexes, and townhouses are all examples of single-family buildings. In order to be considered “single-family,” structures must have a ground-to-roof wall separating them, a separate heating system, individual public utility meters, and no units above or below.

In contrast, multi-family units are units with more than one unit within the same structure. For example, multi-family residential structures often feature multiple stories, side-by-side construction without a wall from the ground up, or shared amenities/utilities.

A recent trend among real estate investors exhibits a preference to multi-family properties, specifically in the Los Angeles rental market. A multi-family unit is a popular choice in urban areas with a high demand for housing due to its economical ease to maintain and manage, smaller acquisition price per investment property, and lower vacancy risks. In addition to a scarcity of housing inventory, highly populated urban areas are increasingly developing multi-family homes as a space-efficient answer to the housing market’s demand.
Written by Fernanda Martinez Montesinos


United States Census Bureau (2023). Characteristics of New Housing. USCB. Link
EGL Properties (n.d) Residential Real Estate in LA: How much money can you make investing in a multi-unit property. EGL Properties. Link

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