Former Borough Zoning: How Pre-Amalgamation Bylaws Affect Your North York or Scarborough Addition

If your property is in North York, Scarborough, or Etobicoke, there's a real chance your lot isn't governed by Toronto's citywide zoning bylaw at all. Instead, you may be subject to pre-amalgamation bylaws like North York By-law 7625, Scarborough By-law 10010, or Etobicoke By-law 7625 — each with its own definitions for setbacks, lot coverage, and building height. These old rules weren't wiped out when Toronto amalgamated in 1998. They're still active, and they calculate your buildable envelope differently than Chapter 569. We see homeowners discover this late in the design process, sometimes after drawings are already complete. The fix is straightforward: confirm which bylaw applies before you sketch a single line.

Why Pre-Amalgamation Bylaws Still Exist

Toronto's 1998 amalgamation merged six municipalities — Toronto, North York, Scarborough, Etobicoke, York, and East York — into one city. The plan was always to harmonize zoning under a single bylaw, which eventually became Chapter 569 (the Zoning By-law). But harmonization happened neighbourhood by neighbourhood, not all at once. Over two decades later, large swaths of the former boroughs remain under their original zoning.

The practical effect is that two houses on the same street can be governed by different bylaws. One might have been rezoned under Chapter 569 during a site-specific application. The neighbour's lot never triggered that review, so it stays under the old borough rules. When you apply for a building permit, the city evaluates your project against whichever bylaw legally applies to your property — not the one that seems most current.

The Three Main Former Borough Bylaws

• North York By-law 7625: Covers most of North York. Defines rear yard setback as a percentage of lot depth in some zones, uses different height measurement points, and has unique coverage calculations.
• Scarborough By-law 10010: Governs much of Scarborough. Often more permissive on side yard setbacks but stricter on lot coverage in certain residential zones.
• Etobicoke By-law 7625: Shares a number with North York but is a separate document. Contains distinct rules for accessory structures and angular plane requirements.

Each bylaw was written by a different planning department with different priorities. The definitions don't align. A term like 'lot coverage' might include covered porches in one bylaw and exclude them in another. This isn't academic — it directly affects how much addition you can build.

How Setback Calculations Differ

Under Chapter 569, rear yard setback is typically a fixed distance — often 7.5 metres in RD zones, though it varies by zone category. The old borough bylaws frequently used percentage-based calculations instead. North York By-law 7625, for example, might require a rear yard equal to 25% of lot depth, with a minimum and maximum cap. On a 40-metre-deep lot, that's a 10-metre setback. On a 30-metre lot, it's 7.5 metres.

This percentage approach can work in your favour on shallower lots or against you on deeper ones. We've seen North York properties where the old bylaw actually permits a larger addition than Chapter 569 would — and vice versa. The only way to know is to run the numbers under the correct bylaw.

“

We had a client in Willowdale convinced they needed a variance. Turned out their lot was still under the old North York bylaw, and the percentage-based setback gave them an extra two metres of buildable depth. No variance required.

Side Yard and Angular Plane Differences

Side yard setbacks also vary. Chapter 569 uses a formula based on building height and lot width. The former borough bylaws often used flat minimums — 1.2 metres regardless of what you're building. That sounds simpler, but it also means you can't earn extra side yard credit for a shorter addition the way you might under the citywide formula.

Angular plane rules — the imaginary sloped plane that limits how tall your addition can be near property lines — exist in some form in most bylaws, but the starting height and angle differ. Etobicoke's angular plane requirements for residential zones are particularly strict in certain areas, which can limit second-storey additions more than you'd expect.

Legal Non-Conforming Status and What It Means

Here's where it gets complicated. Many older homes were built to standards that complied with the rules at the time but don't comply with current zoning — whether that's Chapter 569 or the applicable former borough bylaw. These properties have 'legal non-conforming' status. The house can stay as-is, but any addition or alteration triggers a fresh zoning review.

Under the old borough bylaws, the rules for expanding a legal non-conforming structure are often different than under Chapter 569. Some former borough bylaws are more permissive about minor expansions; others require a variance for any change. We've seen Scarborough properties where the existing house sits closer to the rear lot line than current By-law 10010 allows. Adding even a small bump-out technically increases the non-conformity, which can trigger a Committee of Adjustment application.

When Non-Conforming Status Helps

Occasionally, legal non-conforming status under an old bylaw is actually advantageous. If your house was built to a setback that the former borough permitted but Chapter 569 wouldn't, you may be able to extend along that same plane without a variance — as long as you're not increasing the non-conformity. This is a nuanced determination that depends on the specific bylaw language and how the city interprets 'increase.'

When It Creates Problems

More often, non-conforming status complicates things. If your existing house already exceeds the lot coverage permitted under the old bylaw, any addition — even a code-compliant one — may require a variance because it increases the total built area. The Committee of Adjustment will want to see that your proposal is a 'minor' variance and won't negatively impact neighbours. That's an extra application, extra time, and extra uncertainty.

How to Confirm Which Bylaw Governs Your Property

Toronto's online zoning map shows which bylaw applies to each property, but the interface isn't intuitive. You need to look for the 'Zoning By-law' layer and check whether your lot is coloured for Chapter 569 or shows a former borough bylaw reference. The city's zoning examiners can also confirm this during a preliminary review, though wait times vary.

At PermitsHub, we run this check on every Toronto addition project before starting drawings. It takes five minutes and prevents weeks of rework. If you're in North York, Scarborough, or Etobicoke, assume nothing — even if your neighbour recently built an addition under Chapter 569, your lot may be different.

• Check the City of Toronto's interactive zoning map and select the 'Zoning By-law' layer
• Look for references to By-law 7625 (North York or Etobicoke) or By-law 10010 (Scarborough)
• If the map shows Chapter 569, confirm the specific zone category (RD, RS, RT, etc.)
• Request a zoning certificate from the city for definitive confirmation

Designing Around Former Borough Constraints

Once you know which bylaw applies, the design process can account for its specific rules. This isn't just about avoiding variances — it's about maximizing what you can build as-of-right. A skilled designer will test the envelope under the applicable bylaw, not assume citywide standards.

For North York properties under By-law 7625, we often find that the percentage-based rear setback creates opportunities on certain lot shapes. For Scarborough under By-law 10010, the lot coverage limits tend to be the binding constraint, which pushes designs toward taller, narrower footprints rather than sprawling single-storey additions.

When a Variance Becomes Unavoidable

Sometimes the old bylaw simply doesn't permit what you want to build. Maybe the lot coverage is already maxed out, or the required setback leaves too little room for a functional addition. In those cases, a Committee of Adjustment variance is the path forward. The good news is that the Committee evaluates each application on its merits. A well-prepared submission with accurate drawings and a clear rationale can succeed even when the numbers don't technically comply.

The key is knowing early whether you'll need a variance. Discovering this after permit submission wastes months. Discovering it during design lets you either adjust the scope to avoid the variance or prepare the Committee application in parallel with your permit drawings.

Common Surprises We See on Former Borough Projects

After handling hundreds of addition permits across the former boroughs, certain patterns emerge. These aren't universal rules, but they're common enough that we check for them on every project.

• Scarborough lots with unusually deep rear yards often have stricter coverage limits than expected under By-law 10010
• North York properties near ravines may have both former borough zoning and TRCA regulations, creating overlapping constraints
• Etobicoke angular plane rules can restrict second-storey additions more severely than Chapter 569 would
• Some former borough zones have minimum lot area requirements that prevent severance or limit additions on undersized lots
• Accessory structure rules (detached garages, sheds) vary significantly between bylaws and can affect total coverage calculations

“

The former borough bylaws reward homework. Clients who confirm their zoning early almost always end up with a smoother permit process — and often a larger addition than they thought possible.

Working with the City on Pre-Amalgamation Properties

City of Toronto zoning examiners are familiar with the former borough bylaws, but they're reviewing hundreds of applications. Submitting drawings that reference the wrong bylaw or use incorrect setback calculations will trigger a rejection or revision request. The cleaner your submission, the faster it moves.

When we prepare drawings for North York, Scarborough, or Etobicoke additions, we include a zoning summary sheet that explicitly states which bylaw applies and shows the calculations under that bylaw's definitions. This removes ambiguity and demonstrates that the design team understands the regulatory context. Examiners appreciate it, and it reduces back-and-forth.

If your property is in one of Toronto's former boroughs and you're planning an addition, the first question isn't 'how big can I build?' It's 'which rules apply?' Get that answer early, and the rest of the process follows logically. Skip it, and you risk designing something that doesn't fit your actual zoning envelope.