Excavation Permits in Ontario: What Requires One and What Doesn’t

If you’re planning any excavation work in Ontario — digging for a pool, adding a basement walkout, installing a retaining wall, or trenching for utilities — understanding permit requirements upfront saves you thousands in fines and project delays. This guide covers what requires a permit in the GTA, who pulls it, and what happens if you skip it.

The Short Answer: It Depends on What You’re Building

In Ontario, the permit requirement for excavation is tied to the structure being built, not the digging itself. You don’t get a “digging permit” — you get a building permit for the project that requires the dig. Here’s how it breaks down:

Projects That Require a Building Permit

Inground Pools

Inground pools require a building permit in virtually every GTA municipality. The permit covers structural requirements, pool enclosure (fence), and compliance with setback rules. Permit fees typically run $300–$800 in Toronto, Richmond Hill, Vaughan, Markham, and other GTA municipalities. Current wait times: 6–12 weeks.

Basement Underpinning and Lowering

Any work that involves deepening an existing foundation requires a building permit and a licensed engineer’s drawings in Ontario. No exceptions. This applies to full basement excavation projects, walkout conversions, and underpinning. Attempting this without a permit is one of the few things that can result in a stop-work order and mandatory removal of completed work.

Retaining Walls Over 1 Metre

Retaining walls exceeding 1 metre (approximately 3 feet) in height require a building permit in most GTA municipalities. Walls over 1.5 metres typically require engineered drawings. Some municipalities (York Region municipalities, City of Toronto) also require permits for walls adjacent to public right-of-ways at any height.

Additions and New Structures

Any excavation for a building addition, detached garage, or new structure requires a permit. The excavation is part of the building permit application — not a separate process.

Projects That Typically Do NOT Require a Permit

• Surface regrading (changing the slope of your yard without touching the foundation)
• French drains and drainage improvements on your own property
• Utility trenching (though you still need utility locates via Ontario One Call)
• Retaining walls under 1 metre that are not structural
• Above-ground pools (check local enclosure bylaws)

When in doubt, call your municipal building department and ask. A 5-minute phone call can save you from a stop-work order.

Ontario One Call: Mandatory for All Digging

Before ANY digging in Ontario — permitted or not — you are legally required to contact Ontario One Call (1-800-400-2255 or ontario1call.com) at least 5 business days before breaking ground. This is free and ensures gas, hydro, water, and telecom utilities are marked so you don’t hit them.

Hitting a buried utility without a locate request is a serious liability. In Ontario, you can be held liable for the full cost of repairs plus consequential damages. Legitimate excavation contractors will not dig without confirmation of completed locates.

Who Pulls the Permit — You or the Contractor?

Either party can apply for a permit, but the permit is issued to the property owner. In practice, most GTA contractors handle the permit application as part of their service — it’s a sign of a professional operation. Confirm this in writing before work starts. If a contractor says “you handle the permit” for a pool or basement project, ask why.

What Happens If You Skip the Permit

Building without a required permit in Ontario carries real consequences:

• Stop-work order: Issued by municipal building inspector, immediately halts construction
• Fines: Up to $50,000 per offence under the Ontario Building Code Act
• Mandatory removal: You may be required to demolish the unpermitted work
• Insurance issues: Home insurance may not cover damage to or caused by unpermitted work
• Resale problems: Unpermitted work surfaces during real estate disclosure and can derail a sale

GTA Permit Timelines in 2026

Permit approval has been slow across the GTA since 2022. Current realistic timelines:

• City of Toronto: 8–16 weeks for residential building permits
• York Region municipalities (Richmond Hill, Vaughan, Markham, Aurora, Newmarket): 6–12 weeks
• Peel Region (Brampton, Mississauga): 8–14 weeks
• Barrie: 4–8 weeks

Plan your project around permit approval, not around when you want to break ground. April bookings for summer pool installations often miss the season if permits are not started by January or February.

OCM Excavation handles site preparation, pool excavation, and full excavation services across the GTA. We work with homeowners on permit timing and can advise on municipality-specific requirements for your project area.

Call 416-317-3090 or request a free quote.