What is an Accessory Dwelling Unit (ADU)?

The Zoning By-law 1-Z-2014 By-law defines it as follows:

A second unit shall mean a self-contained dwelling unit, supplemental to the permitted primary residential dwelling unit of the property, in which the second unit has its own kitchen and bathroom.

Where are they permitted?
  • Urban Residential Type 1 Zone (R1)
  • Urban Residential Type 2 Zone (R2)
  • Urban Residential Type 3 Zone (R3)
  • Urban Residential Type 4 Zone (R4)
  • Hamlet Residential (RH)
  • Agriculture (A)


See Zoning By-Law 1-Z-2014, provision 3.2.3 for full details.

ADUs are allowed in single-detached, semi-detached, street townhouses and accessory buildings or structures. They must be located on the same lot as the primary dwelling and must comply with the following:

  • Can not have a way of internal access to the primary dwelling unit, except that access to a primary and second dwelling through a common vestibule entry is permitted;
  • One(1) parking space shall be provided for the ADU on the lot, in addition to the minimum required parking spaces for the primary dwelling unit, and in accordance with the Off-Street Parking bylaw;
  • The maximum number of residential dwelling units permitted per lot shall be two(2) including the ADU
    (for example; one ADU + primary dwelling unit)
  • Is not permitted in a farm building, vacation home or
  • Any other dwelling intended for vacations, recreation, seasonal or short-term accommodation purposes. Where an ADU is located on a lot, a garden suite, boarding or lodging house, or rooming house are not permitted. If a garden suite, boarding or lodging
    house or rooming house exists on the lot, an ADU is not permitted
  • Are not permitted in buildings with a legal nonconforming use unless relief from the Zoning By-law has been approved through a Zoning By-Law Amendment or Minor Variance in order to establish such ADU;
  • Are only permitted in dwelling units connected to the municipal or private water services and sanitary sewer system or private septic systems;
  • A minimum of 50% of the front yard shall be maintained as landscaped open space.
  • Shall not be larger than 45% of the total useable floor area of the primary dwelling unit excluding any deck or unenclosed porch. It must also comply with section 3.2.1(g) for accessory structures permitted in the applicable zone.
  • The Chief Building Official and his designate is responsible for the registration of each new accessory dwelling unit.
  • Once a unit has been approved and a building permit issued, the permitted use shall apply to the property and not to the property owner.
  • The approval and registration of an accessory dwelling unit may be revoked at any time by the General Manager of Planning and Development, the Chief Building Official, a By-law Enforcement Officer, the Fire Chief or any of his/her designates should it become obvious or apparent that the accessory unit is no longer in compliance with applicable legislation, by-law, building code or fire code, or any other applicable law under their authorities.

For questions regarding requirements for a municipal civic address, please contact our Geographic Information Systems Division by phone at 519-426-5870 or email [email protected]

The following information is required to ensure that your registration and building permit application is given full consideration. An incomplete or improperly prepared application may not be accepted or may result in delays during the processing of the application.

A complete application for this type of development includes:

  • Accessory Dwelling Unit Zoning & Building checklist: A complete ADU Building Permit Checklist consists of completing a checklist of items required for the ADU building permit.
  • A Building Permit Application Form & Fees — A complete Building Permit Application Form is a ministry-prescribed form that is required in order to apply for a building permit. Fees will be calculated according to the value of construction.
  • A Septic Application Form & Fees— A complete Septic Application Form is a ministry-prescribed form that is required in order to apply for a building permit. Fees will be calculated according to the type of septic you require.