The by-law defines what social housing is. In short, it is any dwelling unit owned by a non-profit organization, a cooperative, a government, a paramunicipal corporation, a public academic establishment, a university, or a social trust that is intended for people with special housing needs or households with low or modest incomes. Social housing is generally developed within the framework of government subsidy programs, but it can also be developed outside these programs.

Affordable housing, which is different from social housing, is a dwelling unit that meets one of the following requirements: 

• A dwelling unit for which the rent is subject to an agreement for at least 20 years with the government, the city, or one of their agents to ensure its affordability.
• A dwelling unit funded by a government, the city or one of their agents, or created as part of one of their programs aiming to sell affordable properties subject to a resale pricing limit for at least 20 years.
• An off-market dwelling unit held by a non-profit organization, a cooperative, a government, or a paramunicipal organization, a public academic institution or university, or a social trust, provided that certain criteria are met under the by-law.

For the purpose of the by-law, a family housing unit is a dwelling unit with at least five rooms, including three bedrooms and an area that is sufficient for a family. The by-law sets this minimum area at 86 m² or 96 m², depending on the area where the dwelling is located.