Our latest Housing Market Insights explores secondary units in Ontario.
Our goal is to provide you with a more accurate estimate of the number of secondary units in Ontario’s most populated municipalities. We also examined the factors that contribute to the regional disparities across the province.
Secondary units are self-contained residential units within dwellings, predominantly single-family homes. They can also be within structures ancillary to a dwelling, an apartment above a detached garage.
They are commonly referred to as:
- basement apartments
- accessory apartments
- in-law suites
- laneway homes
Past attempts to estimate the number of these units, including by CMHC, were unsuccessful owing to a lack of reliable data.
We devised a method that identified which properties in the Municipal Property Assessment Corporation’s (MPAC) database had a secondary unit. Once these homes were identified, we were able to analyze whether certain location and property-specific attributes affected the likelihood of a home having a secondary unit.
- The percentage of properties with a secondary unit varied greatly across municipalities in Ontario.
- Nearly 1 out of 6 ground-oriented homes1 in Toronto had a secondary unit. This is the highest ratio in Ontario, totaling an estimated 75,000 secondary units.
- Basement apartments were the most common type of secondary unit.
- Municipalities that tended to have a higher ratio of properties with a secondary unit had a low supply of other rental housing:
- Municipalities with low vacancy rates were more likely to have secondary units.
- Single story homes were more likely to have a secondary unit than other styles of homes, owing to their size and design features.
- Secondary units are more prevalent in older established neighbourhoods that are highly coveted by renters.
- Municipalities with a large percentage of newer ground-oriented homes were less likely to have secondary units.
City of Toronto had largest number and greatest prevalence of secondary units
Contrary to our expectations, municipalities with more ground-oriented homes did not always have more secondary units.
The main exception was the city of Toronto, which had the greatest number of ground-oriented homes and the most secondary units at nearly 75,0002.
Ottawa, on the other hand, easily had the second-largest number of ground-oriented homes. However, it had fewer secondary units compared to Mississauga and Brampton.
Greater Sudbury had more secondary units than municipalities with a far greater number of ground-oriented homes, such as Hamilton and London.