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Learn how to add an Additional Residential Unit (ARU) to your property.
On this page:
Additional Residential Units (ARUs) are separate, self-contained living spaces within a home or on the same property. They help add more homes while using existing roads, utilities and services.
Each ARU has its own kitchen, bathroom and living area. You can use an ARU for family members or rent it out for extra income.
ARUs can be:
Check your property’s zoning using the interactive map before you start planning an ARU.
The city’s updated zoning bylaw allows:
For detailed zoning information, check Zoning Bylaw 2018-050, especially:
This mapping tool is for general informational purposes and cannot be relied upon for construction, real estate (buying or selling of land) or permitting purposes. The data on the map is from May 30, 2025 and may be updated by the City of Waterloo.
To learn how to add an ARU, get permits and understand costs, refer to the Additional Residential Unit toolkit (PDF).
Before construction starts, make sure you have:
Use our Additional Residential Unit toolkit to learn how to:
Download Additional Residential Unit toolkit (PDF)
You may qualify for the ARU grant. You can get up to $30,000 to build an additional residential unit if it will be rented at an affordable rate.
Learn more and apply for the ARU grant.
Check out Ontario's Second Unit Guide, a detailed online resource on building an ARUs, including regulations and requirements.
CMHC's Housing Design Catalogue includes sample designs for ARUs and fourplexes.
Email ARU@waterloo.ca if you have questions or need help with your project.
