Additional residential units

Learn about additional residential units (ARUs) and how to add them to your property.

On this page

  1. What are additional residential units?
  2. ARUs add more homes
  3. Zoning regulations
  4. Required permits and licences
  5. How to add an additional residential unit
  6. Contact us

What are additional residential units?

Additional Residential Units (ARUs) are separate, self-contained living spaces within a home or on the same property.

Ontario now allows up to 3 units on every residential lot.

Each ARU has its own entrance, kitchen, bathroom, and living area. ARUs can be inside a single detached, semi-detached, or townhouse building, or in a backyard Coach House.

ARUs provide extra housing on a property. They can be used by family members or rented out.


ARUs add more homes

ARUs add more housing while using existing roads, utilities and services. Waterloo is one of the fastest-growing cities in Canada, and more homes are needed.

Right now, many residents can’t afford a home in the city. ARUs help by:

  • adding more housing choices
  • creating more affordable rental options

They also also give homeowners the option to add rental units to their property.


Zoning regulations

To address the housing crisis, the City of Waterloo has updated its Zoning By-law. These changes allow:

  • up to 4 units on a low-rise residential property
  • buildings up to 4 storeys in all low-rise residential areas

Required permits and licenses

A building permit is required to begin construction of an additional residential unit. Apply for a home renovation or additions permit on the building permits page.

If you are planning on renting out an additional unit, you must apply for a rental license. Learn about the requirements and how to apply on the rental licences page.


How to add an additional residential unit

The city is developing an online ARU toolkit to guide homeowners through the process. It will include:

  • steps to create an additional residential unit
  • building requirements
  • key considerations for homeowners

City staff are also exploring incentives to help offset the costs of building additional rental units.

Learn more about the ARU toolkit’s development and share your feedback on Engage Waterloo

Additional resources

Check out the Ontario Second Unit Guide – a detailed online resource on building an ARU, including regulations and requirements.


Contact us

If you have any questions, email us at ARU@waterloo.ca.