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The digging itself often goes quickly. The risk lies in everything around the hole: buried utilities, trench walls that can collapse without warning, the footings of the house next door and the question of where a large volume of soil will end up. All of it has to be settled before a machine arrives, which is why excavation is more tightly regulated than most yard work.
This page covers the kinds of residential digs, how a job is planned, mandatory locates and what to do if a line is hit, trench safety rules, protecting neighbouring foundations, excess soil rules and permits. The foundation waterproofing page covers the work done once a wall is exposed, and the grading page the final shaping of the yard.
Types of residential excavation: foundations, additions, pools, utility lines and waterproofing digs
- New foundations and additions: a full excavation down to footing level, sized for the walls, the formwork and room to work.
- Basement lowering and underpinning: digging below existing footings in stages, always to an engineer's design.
- Pools: an in-ground pool excavation, plus trenches for the plumbing and electrical lines to the equipment.
- Utility trenches: new or replacement water and sewer services, gas lines, and power or data to a garage or outbuilding.
- Waterproofing and drainage digs: a trench along the foundation to expose the wall and replace the weeping tile.
- Driveway, patio and retaining wall bases: removing soft soil so a compacted granular base can go in.
How a residential excavation is planned and carried out
- A survey or site plan fixes the property lines, setbacks and depths, and for a new foundation the corners are staked.
- Utility locates are requested and the marks checked on site, along with any private lines the owner knows about.
- The machine route is planned so the driveway, lawn, trees and septic or buried services aren't crushed on the way in.
- Soil is dug and sorted as it comes out, keeping topsoil apart from clay or fill so reusable material isn't wasted.
- Groundwater is pumped out where it collects, and the bottom of a footing excavation is kept dry and undisturbed.
- Inspections required by the permit happen before concrete is poured or trenches are closed.
- Backfill goes back in compacted layers, followed by rough grading so water drains away from the house.
Mandatory locates before digging, and what to do if a buried line is hit
No excavation should start until public lines are marked. In Ontario, a free locate through Ontario One Call is required by law at least 5 business days before digging, and in Quebec the RBQ asks contractors to request one from Info-Excavation at least 4 business days ahead. Ontario's guidance for construction projects adds that employers must make sure all gas, electrical and other services are located and marked in and near the area to be excavated. Marks are only approximate, so crews expose lines by careful hand or vacuum digging when working close to them.
If a gas line is hit, leave the machine off, get everyone away from the area and out of the wind, and call emergency services and the gas utility from a safe distance; don't try to stop the leak or bury it. If a power line is struck, stay clear of the equipment and anything touching it. Even a scrape on a line or its coating needs to be reported to the owner of the line, because damage that doesn't leak today can fail later.
Trench safety: cave-ins, sloping, shoring and trench boxes
Soil that looks solid can give way in seconds, especially in wet, sandy or previously dug ground, and Ontario's Ministry of Labour warns that workers can be critically injured or killed in excavation cave-ins. Its guidance under the Construction Projects regulation, O. Reg. 213/91, says never to enter a trench deeper than 1.2 metres (47 inches) unless the walls are sound, made of solid rock, properly sloped, shored or protected by a trench box, and to keep heavy equipment, excavated soil or rock and construction materials at least one metre from the upper edges.
Other provinces set their own rules through their workplace safety regulators, and a professional crew should explain how the walls will be protected before anyone goes in. As a homeowner, stay out of the trench even to take a quick look, keep children and pets away, and make sure an open excavation is fenced or covered at the end of each day.
Digging next to a neighbour's house: shoring, sloping and underpinning compared
The soil beside and below a footing is part of what holds a house up. Dig close to a neighbour's foundation, or deeper than it, and that support can slip away, leading to cracks, settlement or worse. On tight city lots, how the soil is held back matters as much as how the hole is dug, and it is a question for a structural or geotechnical engineer, not something to improvise on site.
- Sloping cuts the excavation walls back at an angle, which is simple but only works where there's room.
- Shoring holds vertical walls in place with an engineered system, so the dig can stay within a narrow lot.
- Underpinning extends a foundation deeper in short sections, so it no longer depends on the soil being removed next to it.
- A pre-construction survey with dated photos of the neighbouring house records existing cracks before work begins.
- Tell neighbours early, and put any access to their lot for machines or shoring in a written agreement.
Excess soil from excavation: reuse, hauling and Ontario's excess soil regulation
Every excavation produces soil, and the cheapest place for it is usually back on the same property, as backfill or grading material, as long as it's suitable. What can't be reused has to go somewhere legitimate. In Ontario, excess soil is regulated under O. Reg. 406/19, On-Site and Excess Soil Management. The province defines excess soil as soil that has been dug up, typically during construction, and must be moved off-site because it can't or won't be reused there.
The rules require excess soil to meet quality standards and to go to an appropriate reuse site with the site owner's written consent, or else to a licensed disposal facility, and some projects must file notices in a public registry. There are exemptions for small projects, including those removing less than 100 cubic metres sent directly to certain waste disposal sites. Other provinces and many municipalities have their own soil and fill rules. Ask your contractor where the soil will go, and if the site once had an oil tank or other contamination, have it tested before any soil leaves.
Permits for excavation: foundations, pools, road access and protected trees
A new foundation, an addition or an underpinning job needs a building permit, and the excavation is usually inspected as part of it. Pools often need their own permit and must meet the municipality's pool fencing rules before they are filled. Work that crosses a sidewalk, lowers a curb or reaches into the road allowance to connect services generally needs separate approval from the city.
Many municipalities also protect trees, including their root zones, so digging near a large tree on your lot or a neighbour's can require a permit or an arborist's plan. Bringing in or removing fill can trigger a site alteration by-law, covered on the grading page. Your contractor or designer should list every approval before the job is scheduled.
Excavation: frequently asked questions
Do I need locates for a small digging job?
Yes. Gas, power and communications lines can sit close to the surface, so request a locate before any digging, even for fence posts or a tree. In Ontario it's free and required by law.
How close can an excavation come to my neighbour's house?
It depends on the soil, the depth and the neighbouring footing. An engineer decides whether sloping, shoring or underpinning is needed, and the neighbour should be told before work starts.
Who is responsible for the soil that comes out?
The project owner and the contractor. Agree in writing where it will go, and in Ontario make sure it's handled under the excess soil rules, which send it to an approved reuse site or a licensed disposal facility.
Can I step into the trench to check the work?
No. Trench walls can collapse without warning, and Ontario's rules bar workers from trenches deeper than 1.2 metres unless the walls are sloped, shored or protected by a trench box. Look from a safe distance.
Can excavation be done in winter?
Yes, but frozen ground is slower and harder to dig, and footings and fresh concrete have to be protected from frost. Many homeowners plan digs for spring through fall when they can.
Does digging for a pool need a permit?
Usually. Most municipalities require a pool permit and a compliant fence or enclosure, and some also need a lot grading review. Check with your city before booking the excavation.
Sources
Written by the LokalMatch editorial team. Reviewed by Zubair Afzal on September 10, 2026. How we write and check our guides