Do You Need a Permit for a Retaining Wall? A Guide to Local Rules

Whether you’re sprucing up your backyard or tackling a more complex landscaping project, building a retaining wall can be a great way to manage sloped land and improve your property’s curb appeal. But before you break ground in Durham Region, Ontario—including cities like Pickering, Ajax, or Oshawa—it’s important to know when a building permit is required. Here’s what you need to know to stay on the right side of the law (and avoid headaches later).

When You Do Need a Permit

1. Your Retaining Wall is Over 1 Metre Tall

If your retaining wall will be taller than 1 metre (about 3 feet 3 inches), you’ll likely need a building permit. For example, the City of Pickering requires permits for walls over this height because they can impact soil stability and public safety.

2. It Borders a Public Area

Walls located near public spaces such as sidewalks, roads, or parks may qualify as “designated structures” under the Ontario Building Code. This means additional engineering reviews and permits are often mandatory.

3. There’s a Risk to Public Safety

If the wall could pose a safety risk—say, it supports heavy loads near a public path or a commercial area—it must meet specific structural standards. In such cases, a professional engineer may need to design or approve the plans.

When You Might Not Need a Permit

You may be off the hook for a permit if:

Your wall is under 1 metre in height
It’s located entirely on private property
It doesn’t impact drainage or neighboring properties
It’s not near a public right-of-way

That said, “no permit needed” doesn’t mean “no rules apply.” You’re still responsible for complying with zoning bylaws, property line setbacks, and grading regulations.

For instance, in Oshawa, if your wall affects the slope of the land or sits within 0.6 metres of a property line, a site alteration permit might still be required—even if you don’t need a building permit.

What You Should Do Before Building

Talk to Your Municipality
Every city in Durham Region may have slightly different requirements. Contact your local building department before starting your project. This step could save you time and money.
Gather Documentation
If a permit is required, you’ll need to submit drawings—and in many cases, these must be prepared by a qualified designer or engineer, especially for taller or complex structures.
Follow All Relevant Regulations
Even without a permit, zoning bylaws and grading rules must be followed. Ignoring them could lead to fines or having to tear the wall down.

Helpful Links by Municipality

Final Thoughts

A retaining wall can add both function and beauty to your property—but only if it’s built safely and legally. In Durham Region, the rules aren’t one-size-fits-all, so it’s best to do a little research and talk to your local building department before you start. That way, you’ll ensure your project is built to last—and built to code.

Do You Need a Permit for a Retaining Wall ?