You may be able to build up to four dwelling units on lots that currently permit a single detached dwelling, semi-detached dwelling, or street townhouse dwelling.

The process on this page applies to residential buildings with two to four total residential units. Visit our residential dwelling units page for information about buildings with five to 10 dwelling units.

On this page:

  1. About additional dwelling units
  2. Getting started
  3. Guide to Additional Dwelling Units
  4. Zoning regulations
  5. Types of ADUs
  6. Parking & walkways 
  7. Waste collection
  8. Required permits
  9. Build your ADU(s)
  10. Who to contact

About additional dwelling units

An additional dwelling unit (ADU) is a separate and self-contained dwelling unit located on the same property as a single detached dwelling, semi-detached dwelling or street-townhouse dwelling. It may be located within the existing building, an addition to an existing building, a separate detached structure or may be one of up to four units in a new building.

An ADU is commonly called a duplex, triplex or fourplex when located in the main building, and a backyard or tiny home in a separate building from the main building.

Visit these pages for information about:

  • residential dwelling units: residential buildings with five to 10 total units and no other uses
  • site plans: buildings or properties with five to 10 residential dwelling units and non-residential uses or more than 10 residential dwelling units

Guide to Additional Dwelling Unit

We want to make it easier for you to understand how to start the process of building an additional dwelling unit (ADU), so we have a helpful Guide to Additional Dwelling Units, which answers many of the initial common questions.

Watch a webinar

City staff are hosted an informational webinar on Thursday, September 26. If you missed it, you can watch the recording.

Watch the webinar

Getting started

If you want to add ADUs to your property, there are a few things to do before you apply for a building permit:

  • find design and building professionals
  • develop your project budget
  • learn about restrictions on your property
  • consider trees on or adjacent to your property

Find design and building professionals

The first step is finding professionals who could help you design and build your project. This team may include:

  • designer: to help prepare your plans and navigate the process
  • designer or architect: required if you’re proposing three or more units in a building
  • contractors
  • other professionals, as required

We do not endorse or recommend specific professionals, but we encourage you to evaluate your team based on their experience:

  • in the type of ADUs you’re planning
  • working in Kitchener

We recommend talking to at least three designers and contractors before finalizing your project team.

Develop your project budget

Building an additional dwelling unit is an investment in your property, so you’ll want to develop a detailed budget and financing plan. There are costs associated with designing, building, financing and operating your units. Costs will vary based on the type of additional unit (internal renovation, addition, new building), size, construction methods and site.

As you are developing your budget, consider costs like:

  • materials (wood, shingles, pipes, electric panel)
  • labour
  • equipment (purchase or rental)
  • consultant fees (examples: designer, surveyor, heritage consultant)
  • land costs
  • financing (talk to your bank or lending institution)
  • insurance
  • utility connection fees

You will also have associated application fees, which could include:

  • building permits
  • zoning (occupancy) certificate
  • new driveway or driveway widening permit
  • development charges
  • regional permits if your property is on a regional road

Learn about restrictions on your property

Check your property survey to understand:

  • where your property lines are
  • setbacks to existing buildings
  • easements
  • rights-of-way
  • encroachments
  • protected services such as utilities, infiltration galleries or drainage swales

If you do not have a survey, you can request a copy of a property survey online.

You should also check with your lawyer to see if there are any encumbrances on title such as restrictive covenants, airport zoning regulations, or a registered subdivision agreement (which could include tree-protection areas or noise mitigation measures that may affect your proposal).

Consider trees on or adjacent to your property

If your property is larger than one acre and your project has any impact on existing trees either on or adjacent to your property, you may need a tree conservation permit. You should make every effort to protect and preserve trees whenever possible.

If your project may impact trees on the property line (in shared ownership) or on adjacent lands (such as construction within root zones), you must get permission from the neighbouring property owner.

If your project may impact trees on public lands (examples: street trees or trees in an adjacent park or natural area), please send us an email.

Zoning regulations

Under our zoning bylaw, up to four dwelling units are permitted on residential lots in Kitchener. However, in some cases, only one or two dwelling units may be possible due to zoning regulations such as minimum lot width, servicing restrictions or other constraints like natural hazards. Some lots may not be suitable for ADUs.

Your ADU must comply with our zoning bylaw and the Ontario Building Code.

Check the zoning of your property online using our interactive mapping tool. If you have any questions or need help, call 519-741-2426 or send us an email. If you prefer, you can meet with staff in person at City Hall. Book an appointment to plan your visit or drop in during business hours.

Types of ADUs

Under our zoning bylaw, many combinations of ADUs may be possible, up to a maximum of four units on a lot. 

Visit the ReHousing website to find illustrations of different ADU configurations and learn more about converting your home to a multi-unit dwelling.

One ADU (attached)

  • one ADU within or attached to the main building for a total of two units
  • also known as a duplex
  • example: the basement of an existing dwelling could be converted into a separate residential unit

Two ADUs (attached)

  • two ADUs for a total of three units
  • also known as a triplex
  • example: the basement of an existing dwelling could be converted into a dwelling unit, and an addition could be added for two additional dwelling units, or a new building could be constructed with three separate dwelling units

Three ADUs (attached)

  • three attached units for a total of four units on your property
  • also known as a four-plex
  • the three new units could be located in or in an addition to the main dwelling or in an entirely new building

ADU (detached)

  • one detached dwelling
  • also called a tiny house or backyard home
  • the backyard home can have one or two units, and you can have up to four dwelling units on the lot
  • you could have up to three units in the main building and one in a backyard home
  • you could have up to two units in the main building and a two-unit backyard home
  • if the permitted building height allows, you can also build a unit above a detached garage

Parking & walkways

Under our zoning bylaw, there are regulations for parking spaces, driveways and pedestrian walkways.  

The by-law requires that a 1.1 metre wide unobstructed walkway is provided to the main entrance of all additional dwelling units where the door does not face a public street.   The walkway must have overhead clearance of 2.1 metres, and cannot be obstructed by window wells, parking spaces, HVAC equipment, utility meters or anything that blocks the path of travel.  This ensures residents, visitors and emergency services can easily find and access the dwelling unit. 

  • the minimum number of vehicle and bicycle parking spaces
  • the minimum size of parking spaces
  • number of driveways
  • driveway width (maximum is generally 40 to 50% of the width of a lot, to a maximum of 8 metres)
  • driveway or parking lot setbacks
  • maximum garage width
  • the material of driveways and walkways 

These regulations will limit the number of parking spaces that you can provide. Parking minimums are lower in parts of the city that are walkable and well-served by public transit.

If there is enough room, properties with three or four units can have parking in a driveway or a small parking lot behind the main dwelling.

If you want to widen your driveway, you will need a driveway widening and curb-cutting permit.

Waste storage and collection

Our property standards bylaw requires that waste containers located on residential properties with three or four units are stored within a building, structure or enclosure to ensure they are screened from view and free of odours.

The Region of Waterloo provides curbside pick-up for properties with up to six units. You must contact the Region at 519-575-4400 to request waste collection service. Learn more on the Region of Waterloo website.

Required permits

Depending on your project, several permits may be required:

Build your ADU(s)

After you get your building permit and other required permits, you can start construction.

An optional pre-construction inspection can be scheduled before or during construction. This is an opportunity to discuss construction methods or other questions with the building inspector.

You must schedule regular inspections throughout the construction process. For duplexes, download our guide to successful inspections to learn more about this process and what the inspector will look for, as well as common issues with inspections. For triplexes and fourplexes, please contact your building inspector.

Who to contact

If you have questions about specific parts of the application process, please contact:

  • planning division: if you have some ideas for adding additional units and have questions about the process, what’s permitted on your lot, how to start, or to apply for a zoning (occupancy) certificate   
  • building division: questions about the building permit process and how to apply, assigning a new address, and calculating development charges
  • engineering division: questions about sanitary and stormwater connections, and grading and drainage
  • forestry division: information and guidance around street trees and trees on neighbouring public lands
  • bylaw: questions about how garbage must be stored, noise, parking restrictions or enforcement
  • Kitchener Fire: review to ensure plans comply with our Emergency Services Policy (distance to hydrants, unobstructed access, fire address signs, etc.)
  • Kitchener Utilities: installation of new service connections and utility meters