Additional Dwelling Units (ADUs) are self-contained residential units located on the same lot as a primary dwelling. ADUs can take several forms, including basement apartments, units above garages, or detached backyard suites.
ADUs help create more diverse housing options while making efficient use of existing urban land.
ADU Information and Application Guide
The City has released an updated ADU Information and Application Guide to support homeowners interested in creating an ADU.
Please note: The information in this guide is current as of April 2025, always confirm requirements with City Staff before beginning your project as policies and regulations may change.
Additional Dwelling Units - Information and Application Guide
Example ADU drawings
For examples of drawings required as part of a building permit, check out our sample drawings: ADU Conversion - Sample Drawings
What is an additional dwelling unit?
An Additional Dwelling Unit (ADU) is a self-contained residential unit located on the same lot as a primary dwelling. ADUs include their own kitchen, bathroom, sleeping and living space.
They can be located:
- Inside the main dwelling (e.g., basement or attic apartment)
- Attached to the main dwelling (e.g., above an attached garage or in an addition)
- In a separate, detached structure (e.g., garden suite or converted garage)
ADUs cannot be severed or sold separately from the main dwelling but may be rented. They are an important tool for increasing affordable housing options, supporting multigenerational living, and making more efficient use of residential land.
![Additional Dwelling Unit Example Diagram]()
Where and how many ADUs are allowed?
Under Zoning By-law No. 79-200:
A maximum of 2 ADUs can be located on a parcel of urban residential land which is within the Urban Area Boundary on which residential use is permitted and is served by municipal sewer and water services, subject to meeting all zoning regulations.
A maximum of 2 ADUs can be located on a parcel of rural land which is outside the Urban Area Boundary on which residential use is permitted and is served by private sewer and water services, subject to meeting all zoning regulations.
| Restrictions | Parcel of Urban Residential Land | Parcel of Rural Land |
|---|
| Permitted Dwelling Type | - Detached dwelling
- Semi-detached dwelling unit
- Townhouse dwelling unit
- Back-to-back townhouse dwelling unit
- On-Street townhouse dwelling unit
- Duplex dwelling
| |
|---|
| Maximum No. of ADUs | 2 | 2 |
|---|
| Composition | Detached, Semi-detached, Townhouse Dwelling Units: - Two interior/attached ADUs
- One interior/attached ADU and one exterior/detached ADU
Duplex Dwelling: - One interior/attached ADU
- One exterior/detached ADU
| Detached Dwelling: - Two interior/attached ADUs
- One interior/attached ADU and one exterior/detached ADU
|
|---|
| Maximum No. of Dwelling Units | For a TOTAL maximum of 3 dwelling units on a lot. | For a TOTAL maximum of 3 dwelling units on a lot. |
|---|
Zoning regulations
Parking
Servicing
- Urban - ADU must connect to existing municipal infrastructure.
- Rural - ADU must connect to the existing septic system if it was constructed with the capacity to accommodate the additional flows, if not, a new septic system will need to be constructed.
ADUs in accessory buildings
Setbacks:
- Rear yard setback – 1.2 metres plus any required road allowances
- Interior side yard setback - 1.2 metres plus any required road allowances
- Side yard (corner lots only) - 4.5 metres plus any required road allowances
Lot coverage: The overall percentage of maximum lot coverage for each zone applies, the maximum lot coverage for an ADU in an accessory building is 93 square metres provided that it does not exceed the overall maximum lot coverage permitted by the zone.
Height:
- Urban: Cannot exceed 6 metres in height (4.5 metres to top of walls and supporting posts)
- Rural: Cannot exceed 7 metres in height (5.5 metres to top of walls and supporting posts)
Rural ADUs
- Rural ADUs in accessory buildings cannot be located no more than 15 metres from the detached dwelling
- ADUs cannot be permitted within a building/structure used for any agricultural use
- Must meet Minimum Distance Separation requirements.
ADU requirements
Building permits and fees
- A building permit is required in the City of Niagara Falls for any ADU
- Building permit fees for ADUs are calculated based on a rate for the finished floor area, there are different fees for an interior ADU (within the main dwelling) and for an exterior ADU (in an accessory building). To determine which fee rate would apply please see the building permit fees
- Contact the Building Department: Email [email protected] or call 905-356-7521 x 4001
Detached ADU emergency access policy
Servicing
Municipal servicing must be available (or private servicing for rural ADUs)
Codes and standards
For an ADU to qualify as an authorized unit, it must satisfy:
- Ontario Building Code health and safety requirements
- Fire and Electrical Codes
- Occupancy Standards
- Property Standards
Frequently Asked Questions
Do I need to provide parking for my ADU?
Yes, one parking space is required per ADU which may be provided in tandem.
On-street parking does not satisfy parking requirements and is not permitted.
Do development charges apply to ADUs?
No. To encourage the supply of smaller housing units, the Province of Ontario has exempted Development Charges and parkland dedication requirements for ADUs (under Bill 23).
Do ADUs need a separate address?
While the property may have the same municipal address, additional units will be identified with a unit address. A unit address will be assigned by the City following a Building Permit application being made. This address will be assigned a unit identifier to the property to ensure the safety of the people residing in any dwelling units and for emergency response. A municipal unit identification sign must be clearly visible from and affixed to the front of the property. A wayfinding sign may also be required for a detached ADU that is not visible from the front of the property. An ADU’s unit address must be assigned and displayed by the time of occupancy.
Can ADUs be severed and sold separately?
No, the City’s Official Plan does not allow ADUs to be separated from the main dwelling and therefore severance applications will not be supported.
Will ADUs affect my property taxes?
Creating an ADU on your property may change your property taxes because the number of dwelling units affects the property’s value. Property taxes are based on how much your property is worth.
For more information about your property’s assessment, contact the Municipal Property Assessment Corporation (MPAC).
Can I rent out my ADU as a vacation rental or a bed and breakfast?
ADUs in residential zones cannot be used as a Vacation Rental Unit (VRU).
VRUs are only allowed in certain zones, including: Tourist Commercial (TC), General Commercial (GC), or Central Business (CB) zone. If your ADU is located in one of these zones, it might be able to be used as a VRU, but it must follow all of the City’s VRU rules, zoning requirements, and provide two extra parking spaces per unit.
How is garbage collected for my ADU?
Contact Niagara Region’s Waste Management Services to start garbage collection for each new ADU when ready. This can be done online at: Commencement of Garbage, Recycling, and Organics Collection - Niagara Region, Ontario.
During this process, you must provide proof from the City that the ADU is legally established. This proof is usually a Building Permit and/or Occupancy Permit for each new ADU. Each unit on the property will also need a unique address to clearly label the waste collection bins. This helps the waste collection team make sure the property is following waste collection limits.
Contact us
City of Niagara Falls Planning Department
[email protected]
905-356–7521 x 4330
City of Niagara Falls Building Department
[email protected]
905-356–7521 x 4001
