Check London ARU Zoning Before You Choose A Backyard Suite Plan

ARUs Are Allowed Broadly - But Not Automatically On Every Lot

London’s ARU rules create more opportunity for homeowners, but zoning still matters. A detached ARU must fit the property’s zoning, permitted yard location, lot coverage, setbacks, building size limits, services, and permit requirements. A backyard can look spacious and still fail one of the early checks.

That is why this page starts with the zoning code and property layout before talking about floor plans.

The First 6 Zoning Checks

Before paying for drawings or a builder deposit, screen the property for these early ARU zoning questions.

• What is the property’s Schedule A zoning code?
• Is the property in a zone where detached ARUs are permitted?
• Is the proposed unit in the rear yard or interior side yard?
• Does the lot have enough coverage remaining?
• Do the rear and side yard setbacks work?
• Can services reach the unit without creating major cost or feasibility issues?

Start With Your Schedule A Zone Code

Your zone code is the first practical screen. It helps determine the rules for use, lot coverage, building location, height, setbacks, and other limits that can affect whether a detached ARU is realistic.

To look up your zone, use the City of London Zone Finder or CityMap, search your address, and note the Schedule A zoning designation. Then compare that code against the ARU rules before moving to design.

Some Zones Need Extra Caution

Not every property type is a good candidate for a detached ARU. The research notes that certain zones are excluded or require caution, including AG, UR, OS, LI, GI, HI, and ER. Homeowners should verify their exact zoning and current rules before assuming a backyard unit is possible.

If your property falls into a restricted or unusual zone, get confirmation before spending money on drawings.

Detached ARUs Must Be In The Right Part Of The Lot

In London, detached ARUs are generally tied to the rear yard or interior side yard location rules. That means the unit cannot simply be placed wherever it looks best on the property. Access, privacy, windows, servicing, trees, and setbacks can all affect the buildable area.

The buildable rectangle is usually smaller than the visible backyard.

Setbacks Can Shrink The Buildable Area Fast

Side and rear yard setbacks can change the project quickly. A side yard that looks wide enough may still create issues if windows face the neighbouring lot line, if access is tight, or if the proposed unit pushes too close to required clearances. Use the detached ARU setbacks guide for the plain-language screening questions before you pay for a plan.

For example, a side yard that seems workable at first can become a much bigger problem once window placement, privacy, access, and code requirements are reviewed.

Lot Coverage Is Often The Deal-Breaker

Lot coverage is the percentage of the property covered by buildings and structures. For ARU planning, the existing house, garage, additions, and proposed detached unit all matter. A large-looking backyard may not have enough coverage left for the unit size the homeowner wants. If the property is in R1-7 zoning, the 35% screen deserves special attention.

• For R1-7 properties, the research highlights a 35% maximum lot coverage limit.
• That does not mean every R1-7 lot can use the full remaining space.
• The exact calculation depends on the lot, the existing buildings, and the proposed ARU.

Size And Bedroom Limits Still Matter

London’s interim ARU controls include limits that can affect the design, including a maximum of 2 bedrooms per ARU and a size relationship to the main dwelling. Homeowners should confirm the current rules before relying on a catalogue plan or builder model.

This is especially important when comparing CMHC or prefab designs. A plan that works in theory may need to be adapted for London.

Zoning Is Only One Part Of Feasibility

Even if the zoning path looks promising, the project still needs a practical servicing route. Water, sanitary, hydro, gas, internet, trenching, grading, and access can materially change cost and feasibility. That is why the cost guide matters as much as the by-law review.

A property can be legally promising but financially difficult if services are far away, the route is blocked, or access is tight.

The $45,000 Loan Does Not Override Zoning

Homeowners often search for the London ARU grant, but the official program is a loan or forgivable loan. That incentive can help eligible projects, but it does not make a non-compliant lot buildable. The property still needs to satisfy zoning, permits, rental licensing, affordability, and servicing requirements.

Common Mistakes Homeowners Make

• Choosing a floor plan before checking zoning - A design may look perfect online but fail the local lot coverage, setback, bedroom, or servicing checks.
• Assuming a big backyard means approval - Visible space is not the same as buildable space. Existing structures, setbacks, lot coverage, and servicing routes matter.
• Treating the grant as approval - The loan program does not replace zoning, building permits, rental licensing, or City review.
• Ignoring the rent cap - If the project depends on the affordable detached ARU forgivable loan, rent-cap math should be checked before design decisions are made.