Additional Residential Units (ARUs)

On August 11, 2025 Council passed and approved amendments to Zoning By-law 14-45 and Grimsby's Official Plan to conform with Provincial legislation, regulation, and policies regarding Additional Residential Units (ARUs).  

What are Additional Residential Units (ARUs)?

Additional Residential Units (ARUs) are separate dwelling units from the principal dwelling unit on a lot, and are located within or attached to the same building as the principal dwelling unit or in a detached accessory building on the same lot.

ARUs are separate living spaces from the principal dwelling unit with a kitchen, bathroom, sleeping and sanitary facilities. ARUs can take many forms and can be attached or within the same building as the principal dwelling unit (such as a basement, or attic conversion) or within a detached accessory building (such as a detached garage).

The ownership of the ARU coincides with the ownership of the main dwellings but can be rented to other individuals.

The benefits of Additional Residential Units include:

• Diversifying available housing and rental options to include smaller units to meet the need of a variety of residents.
• Supporting the gentle intensification of existing residential neighbourhoods.
• Providing an opportunity to create supplementary income streams for homeowners.

Information Guide

View the ARU guide for more information about:

• Where ARUs are permitted
• What is required to develop an ARU
• Frequently asked questions about ARUs

The information guide is not a replacement for the Town of Grimsby Zoning By-law 14-45, Grimsby Official Plan, or Niagara Official Plan. Policies and provisions outside of this guide continue to apply. For more information email planning@grimsby.ca.