Nearly one out of six ground-oriented homes in Toronto has a secondary unit, which totals an estimated 75,000 secondary units across the city. This is according to a new Housing Market Insight released today by Canada Mortgage and Housing Corporation (CMHC). Using the Municipal Property Assessment Corporation's (MPAC) database, CMHC researchers created a method to identify which properties in 28 Ontario municipalities contain a secondary unit. Secondary units are commonly referred to as basement apartments, accessory apartments, in-law suites and laneway homes. Past attempts to estimate the number of these units, including by CMHC, were unsuccessful owing to a lack of reliable data.

"This report hopes to provide more accurate data and analysis on secondary units to housing stakeholders, particularly at the municipal government level,'' said Anthony Passarelli, Senior Analyst with CMHC. "Along with the creation of new purpose-built rental apartment structures, secondary units help to address shortages of affordable rental housing.''

Once secondary suites were identified, it could be analyzed whether certain location- and property-specific attributes affected the likelihood of a home having a secondary unit.

Report Highlights:

- Nearly one out of six ground-oriented homes in Toronto had a secondary unit (15.4%), the highest ratio in Ontario, totaling an estimated 75,000 secondary units.
- The estimated percentage of ground-oriented homes containing a secondary unit in Brampton was 9.6%, the second highest ratio among the municipalities in this study.
- The estimated percentage of ground-oriented homes containing a secondary unit in Mississauga was also above average at 7.4%.
- The estimated percentages of ground-oriented homes with secondary units were much lower in Ottawa (3.3%) and Hamilton (3.1%).
- The two more northern Ontario cities of Thunder Bay (8.4%) and Greater Sudbury (8.9%) had a higher prevalence of secondary suites compared to most other cities in this report.
- Basement apartments were the most common type of secondary unit.
- Municipalities with a low supply of purpose-built, condominium and subsidized rental housing, such as Brampton, Ajax and Barrie, tended to have a higher ratio of properties with a secondary unit.
- Municipalities with persistently low vacancy rates, such as Toronto, Mississauga, Guelph and Kingston were more likely to have secondary units.
- Due to their smaller floor area and design features, single-storey homes were more likely to have a secondary unit than other styles of homes.
- Secondary units are more prevalent in the older established neighborhoods that are highly coveted by renters, due to their close proximity to their downtown cores and major amenities.
- Municipalities with a large percentage of newer homes, particularly ones built in the last decade, tended to have a low likelihood of having a secondary unit.

SOURCE: Canada Mortgage and Housing Corporation