Additional Residential Units (ARUs)

What are Additional Residential Units?

Additional Residential Units, also known as ARUs, are defined as: independent dwelling unit within a single detached, semi-detached or townhouse dwelling, or within a building accessory to a single detached, semi-detached or townhouse dwelling on the same lot, which is ancillary and subordinate to a primary dwelling unit.

ARUs are sometimes referred to as additional dwelling units, granny flats, in-law suites, secondary suites, laneway homes, and basement apartments.

Why are ARUs allowed in Lakeshore?

In November 2022, the Ontario legislature passed the “More Homes Built Faster Act”, also known as Bill 23, to address the province's housing crisis by increasing housing supply and improving affordability. The bill aims to streamline the regulatory and approval processes for new housing developments, thereby expediting construction and reducing costs for developers. As a result, the Planning Act was amended to permit, as-of-right, up to three residential units per property. These provincial requirements supersede local official plans and by-laws and apply to any parcel of “urban residential land”, which is defined to mean a residential lot in an area of settlement that is serviced by municipal water and sewage services.

The Municipality of Lakeshore undertook the Policy Review to amend Additional Residential Unit (ARU) policies in the Official Plan and Zoning By-law to conform to Bill 23, the More Homes Built Faster Act, 2022, which came into effect on November 28, 2022.

Types of Additional Residential Units

Attached
Detached
Basement

Where are Additional Residential Units permitted?

Type of ARU	Zoning Type
	A	R1	R2	RW1	RW2	HR	CA	MU	UR
Attached Residential/Agricultural	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Detached Residential	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Detached Agricultural	Yes	No	No	No	No	No	No	No	No
Basement Residential/Agricultural	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes

Zoning Types

Zoning Types (click to drop down)

R1: Residential – Low Density
R2: Residential – Medium Density
RW1: Residential Waterfront – Watercourse
RW2: Residential Waterfront – Lake St. Clair
HR: Hamlet Residential
CA: Central Area
MU: Mixed Use
UR: Urban Reserve
A: Agriculture

Please note: Properties designated as hazard lands under the Municipality of Lakeshore’s Official Plan are not permitted to have Additional Residential Units (ARUs) in basements or cellars. This stands for any zoning designation within the Municipality.

General Requirements to Have an ARU on Your Property

2.0 parking spaces are required for the primary dwelling unit and 1.0 additional parking spaces per residential unit. The required min. parking space width is 3 meters, and the required min. parking space length is 6 meters.

Only one (1) service is permitted for the main dwelling and ARU.

Only one (1) water meter is issued per property for the main dwelling and ARU.

Only one (1) address is issued by the Municipality per property. The property owner is to assign unit “D” for Detached ARU. Property owner is to assign unit “B” for an attached or basement ARU.
The property owner is to affix the address to the ARU. For properties located on a road where Green 911 municipal addressing signs are required, an additional sign will be ordered at the property owners’ expense to indicate the address with the unit number.

The accessory dwelling unit shall have its own exterior entrance to the primary dwelling unit, but shall not be permitted on an elevation, or façade of the building that faces a public street or private road; and shall no means of internal access to the primary dwelling unit, except that access to a primary and second dwelling through a common vestibule entry is permitted.

Specific Requirements to Have an ARU on Your Property

Attached ARUs– Residential and Agricultural Zone (R1, R2, RW1, RW2, HR, CA, MU, A, UR)

Minimum Side Yard Setback: Setback requirements listed for the main dwelling

Minimum Rear Yard Setback: Setback requirements listed for the main dwelling

Maximum Building Height Permitted: Height requirements listed for main dwelling under the zoning of the property

Maximum Permitted Building Size: Maximum Gross Floor Area (GFA) of 50% of the primary dwelling unit

Maximum Lot Coverage (including accessory buildings): Maximum lot coverage listed for the main dwelling under the zoning of the property

Basement ARUs – Residential and Agricultural Zone (R1, R2, RW1, RW2, HR, CA, MU, A, UR)

Minimum Side Yard Setback: Not applicable
Minimum Rear Yard Setback: Not applicable
Maximum Height Permitted: Not applicable
Maximum Permitted Size: ARU can occupy the entire basement space
Maximum Lot Coverage (including accessory buildings): Not applicable

Detached ARUs – Residential Zone (R1, R2, RW1, RW2, HR, CA, MU, UR)

Minimum Side Yard Setback: 1.5 m
Minimum Rear Yard Setback: 1.5 m or required setback specified by the Conservation Authority
- Unless a two-storey ARU is proposed to have a window adjacent to a property line, the minimum required setback from the side yard and rear yard property line is 3 m.
- The ARU must be constructed within 50 m of the primary dwelling and no closer than 3 m to the primary dwelling.
- To clarify your property's minimum setback requirements, please contact Lakeshore's Building Division.
Maximum Permitted Height: 6.5 m and cannot exceed the height of the primary unit
Maximum Permitted Size: Cannot be greater than 50% of the primary dwelling unit up to maximum of 120 m² of the Gross Floor Area (GFA).
Maximum Lot Coverage (including accessory buildings): Maximum lot coverage listed for main dwelling under the zoning of the property.

Detached ARUs –Agricultural Zone (A)

Minimum Side Yard Setback: 1.5 m
Minimum Rear Yard Setback: 1.5 m
Maximum Height Permitted: 7.5 m and cannot exceed height of the primary unit
Maximum Size Permitted: Cannot be greater than 50% of the primary dwelling unit up to max. of 140 m² of the Gross Floor Area (GFA)
Maximum Lot Coverage (including accessory buildings): 30%

Requirements for ARUs on Properties on Septic Systems

You must choose one of three options below regarding septic system requirements:

Options for ARUs on Properties on Septic Systems

Option One: Provide a septic review of the existing septic system by a licensed installer to ensure the system can treat additional waste produced by the unit(s).
Option Two: Install a new septic system designed to treat waste from the primary unit and additional residential unit (an additional building permit is required).
Option Three: Replace or expand the current septic system to treat waste from the primary unit and additional residential unit (an additional building permit is required).

ARU Building Permit Application Requirements

All building permits are submitted through the Cloudpermit platform. You will be required to create an account.

For information on using Cloudpermit, visit our Building permit information page.

The following documents can be submitted through Cloudpermit:

Site Plan
Schedule 1 – Designer Information Form
Detailed Construction Drawings
Gross Floor Area and Height Calculation of the Existing Dwelling
Energy Efficiency Design Summary (only required for new detached or attached, not required for basement ARUs)
Grading Plan (must bear the signature and seal of an Ontario Land Surveyor Engineer). Along with grade elevations, the grading plan must have the proposed house plotted along with proposed setbacks from the property lines (this is only required for new detached ARUs)

Building Fees are also required to be paid through Cloudpermit. The following fees are required and are subject to change:

Building Permit Fee (per square foot of living space)
Plumbing Permit Fee (per washroom)
Indemnity Deposit (refundable up to three years from permit issuance)
Green 911 Municipal Address Sign (if applicable to the residence)

Additional Approval Requirements for an ARU

Residents are responsible for ensuring that they have contacted the following additional organizations to ensure compliance and approval requirements:

Conservation Authority (Essex Region Conservation Authority & Lower Thames Conservation Authority): If the property is located within the conservation authority regulated area, approval is required. This is not required for basement ARUs.
County Approval (Setback Permit): If the property is located on a County Road and the proposal is located in the front yard, a setback permit is required. This is not required for basement ARUs.
County Approval (Entrance Permit): If the property is located on a County Road and the proposal involves changing the existing entrance, approval is required. This is not required for basement ARUs.
Public Works (Entrance Permit): If the applicant is changing the existing entrance, an entrance permit is required.
Ministry of Transportation: If property is located or abuts a highway, approval is required.

Frequently Asked Questions

How will my property taxes be affected?
Residents are required to contact MPAC to determine how their property taxes will be affected.
Is an ARU subject to development charges?
No, ARUs are not subject to development charges. However, certain building fees are required for the development (see above for specific fees).

Do ARUs need a separate address?
The Municipality only assigns one address per property. Property owners are to assign unit numbers for the ARU (use units B & C for attached units and D for detached units).

Can I rent out my ARU as a vacation rental (Airbnb or VRBO)?
No, ARUs are not permitted to be rented out as a secondary unit for vacation rentals.

How is garbage collected for my ARU?
Garbage would be included in the collection of the primary dwelling unit.

Does the ARU need a separate water meter?
No, only one water meter is issued per property for the main dwelling and ARU.

Can I severe my ARU from my primary lot?
No, detached ARUs cannot be severed from the primary lot.

Can my ARU be bigger than my primary dwelling unit?
No, the ARU cannot be bigger than the primary dwelling unit. Refer to specific size requirements above.

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