French Drain Installation Cost in Toronto & GTA: 2026 Guide

Q: How much does a French drain cost in Toronto in 2026?

For yard drainage, $55-$95 per linear foot. For full perimeter foundation drain replacement at 7 feet deep, $135-$210 per linear foot. A typical detached home in Toronto running 130 feet of perimeter falls between $18,000 and $27,000 fully restored.

Q: How deep does a French drain need to be?

A yard drain works at 24-36 inches. A foundation drain must reach the bottom of the footing, typically 7 feet for a standard Toronto basement, 9 to 10 feet for an underpinned basement. The pipe always sits below the frost line of 4 feet.

Q: Interior vs exterior French drain which is cheaper?

Interior is cheaper to install ($80-$140 per linear foot in Vaughan) but it only manages water once it's already in your basement. Exterior costs more but stops water at the wall. We recommend exterior when budget allows because it protects the foundation, not just the floor.

Q: Will a French drain wreck my lawn?

Short term, yes there's a trench. Long term, no. We restore with topsoil and sod or seed, and a properly compacted backfill settles less than an inch over the first year. Hardscape like interlock costs more to put back; budget $40-$95 per linear foot for full restoration in Richmond Hill.

A French drain is the boring fix that keeps your basement dry, your foundation from cracking, and your backyard from turning into a swamp every April. We install exterior French drains across Toronto, Vaughan, Markham, Richmond Hill, and Mississauga, and the question every homeowner asks first is the same: what is this going to cost? The honest 2026 answer is $85 to $165 per linear foot for a proper exterior install. Call 416-317-3090 if you want a specific number for your lot. Pricing varies based on depth, soil, and access.

What a French drain actually is (and isn’t)

A French drain is a perforated pipe sitting in a trench full of clear stone, wrapped in filter fabric, with a slope that moves water somewhere it can’t hurt anything. That’s it. It’s not a magic system, it’s not patented technology, it’s a drainage detail engineers have used for 150 years. The reason it costs what it does in Toronto isn’t the materials. It’s the digging.

There are three common types we install: exterior foundation drains (along the footing, replacing failed weeping tile), yard drains (mid-property, intercepting surface water before it reaches the house), and retaining wall drains (behind a wall to relieve hydrostatic pressure). Each one has a different depth, a different price, and a different reason for existing. A yard drain at 30 inches and a foundation drain at 7 feet are not the same product in different sizes. They are different systems with different stone, different fabric, different pipe, and very different excavation work.

2026 French drain installation cost in Toronto and the GTA

Real numbers from real jobs we’ve quoted and built across the GTA in the first half of 2026.

Yard French drain, 2 to 3 ft deep: $55 to $95 per linear foot
Mid-depth interception drain, 4 to 5 ft deep: $85 to $135 per linear foot
Foundation drain-only replacement (no waterproofing membrane or parging), 7 ft deep: $135 to $210 per linear foot
Full exterior waterproofing including membrane, parging, and new drain: $250 to $400 per linear foot (see our basement waterproofing guide for that scope)
Foundation drain at underpinned wall, 9 to 10 ft deep: $185 to $285 per linear foot
Retaining wall drain (behind wall): $45 to $85 per linear foot
Sump pit connection (add-on): $1,400 to $2,800
Discharge to storm sewer (add-on): $1,800 to $4,500
Discharge to municipal connection in Toronto: $2,500 to $6,500 with permit

The scope distinction matters. Drain-only replacement is what you do when the existing weeping tile is clogged but the foundation walls and waterproofing are still sound. Full exterior waterproofing is what you do when the basement is leaking, the parging is gone, and the membrane has failed. Two completely different jobs, two completely different prices. If you’re not sure which one your house needs, that is exactly the conversation we have during the site walk.

For a typical detached home in Markham or Vaughan with a full perimeter drain-only replacement, the budget you should expect is $14,000 to $32,000 depending on landscape restoration, depth, and whether the existing drain is clogged or fully collapsed. Add another $15,000 to $30,000 if the job upgrades to full waterproofing scope with membrane and parging.

What drives the price up or down

Two French drains can look identical on paper and cost $9,000 apart. Here is what moves the number.

Depth: The single biggest driver. A 3-foot yard drain costs a third of a 9-foot foundation drain because the trench volume goes up cubically, not linearly. Toronto’s frost line sits at 4 feet, so any functional foundation drain has to be below that.
Soil type: Clay (most of Vaughan, Richmond Hill, north Markham) is slow to dig but holds shape well. Sandy fill (parts of Mississauga, Scarborough) requires shoring above 5 feet for worker safety. Rock or buried concrete adds time and breaker rental.
Access: If we can bring the mini-excavator into the backyard, $20 to $30 per linear foot disappears off the price. If everything’s by hand because the gate is 32 inches wide, labour doubles.
Where the water goes: Discharging to daylight is free. Discharging to a sump and pump system adds $1,400 to $2,800. Tying into Toronto’s storm sewer requires a permit and a licensed plumber’s stamp.
Landscape restoration: Reinstating sod, interlock, gardens, and irrigation lines is real money, often $40 to $95 per linear foot on top of the drainage work itself.
Excess soil disposal: Ontario Regulation 406/19 requires soil characterization on most large jobs. Tipping fees at GTA transfer stations run $90 to $165 per tonne in 2026.
Existing landscape complexity: A clean side yard with grass is one number. The same run through an irrigation system, fibre-optic line that nobody marked, mature hosta gardens, and an interlock walkway is another. We price what we see.

The right way to build an exterior French drain

Every exterior French drain we put in the ground follows the same five-layer detail. Skip any one of them and you’ll be digging it up in five years.

Trench at proper depth and slope: Minimum 1 percent slope, ideally 2 percent, toward the discharge point.
Geotextile filter fabric lining the trench: Keeps fines out of the stone.
4 inches of 3/4-inch clear stone bedding below the pipe.
4-inch perforated PVC or HDPE pipe (we don’t use sock pipe except in very specific cases, because socks clog faster).
12 inches of clear stone above the pipe, fabric wrapped over the top, then native soil or sand backfill.

The stone matters. We only use 3/4-inch clear (no fines), not crush, not pea gravel, not whatever was cheap that week. See our gravel haul cost guide for the material pricing on that.

Common mistakes we get called in to fix

Half the French drain jobs we run in Toronto and Mississauga are second installs. Someone put one in five or ten years ago, it failed, and the homeowner is paying twice. The patterns are predictable.

Sock pipe in clay soil. Sock pipe is the corrugated black perforated pipe wrapped in a fabric sleeve. In sand, it works fine. In Vaughan clay or Richmond Hill silt, the fabric sock clogs with fines inside two years and the drain becomes a buried decoration. Rigid 4-inch perforated PVC with the perforations facing down is what we install, every time.

Stone without filter fabric. Skipping the fabric wrap saves a contractor maybe $200 in material on a 100-foot run. It also guarantees that within five winters, fines from the surrounding soil migrate into the stone, the void space collapses, and water stops moving. Replacement cost: the entire drain.

Drain that goes nowhere. We have dug up drains in Toronto that ran 80 feet, hit a closed pit, and just sat there. Water in, water nowhere. Every French drain has to discharge to daylight, to a sump-and-pump, or to a municipal connection. There is no fourth option.

Wrong slope. Less than 1 percent slope and the water stalls. More than 3 percent and the stone erodes underneath the pipe. A laser level on the trench bottom takes 20 minutes and prevents both problems. We do it on every job.

Permits and Toronto-specific rules

Most yard drains don’t need a permit. Foundation drains that tie into a sanitary or storm sewer absolutely do. In Toronto, that’s a plumbing permit through Toronto Building plus a service connection from Toronto Water if you’re cutting into the municipal line. Vaughan, Markham, and Richmond Hill have similar processes, generally faster than Toronto’s.

Toronto homeowners doing foundation drainage as part of basement flood prevention may qualify for the City of Toronto Basement Flooding Protection Subsidy, which was expanded in late 2025 to a total cap of $6,650 per property. The 2026 breakdown is: up to $500 for a plumbing assessment, up to $3,200 for backwater valves (two devices maximum), up to $2,250 for a sump pump, up to $300 for battery backup power, and up to $400 for foundation drain severance and capping. All components reimburse up to 80 percent of the invoiced cost. Mississauga has a similar program through the Region of Peel. Confirm current eligibility through your city’s basement flooding portal before you book the work.

When to spend more, when to save

Not every drainage problem needs the premium fix. A wet basement corner after heavy rain and a chronically flooded yard are different problems with different solutions.

Spend more when: the basement is finished and a re-flood means tearing out drywall, the foundation is over 40 years old, the existing weeping tile is clay tile (these collapse), or the lot has a high water table. Full exterior waterproofing with membrane pays for itself the first time it stops a flood.

Save when: the issue is surface water pooling in the backyard, the basement is unfinished concrete, or the problem is downspouts draining against the wall. A yard interceptor drain, regraded soil, and proper downspout extensions can solve 70 percent of GTA drainage complaints for under $4,000.

How OCM handles GTA French drain jobs

We measure the run, locate utilities with a private locator on top of the free Ontario One Call markings, confirm discharge point, and quote you a firm number. Excavation goes in with the right size machine for the access. Stone, fabric, and pipe go in to spec, photos at every stage, and we close the trench with proper compaction so your lawn doesn’t sink three months later.

Licensed and insured, credentials live on our trust page. We’re an active excavation contractor in the GTA and we do French drains as part of broader site preparation work too.

Get a quote for your city in the GTA

Call 416-317-3090 for a real number on your specific site. We service every corner of the GTA. See Toronto, Vaughan, Markham, Richmond Hill, and Mississauga for area-specific details. Related cost guides: driveway excavation, topsoil removal.

FAQ

How much does a French drain cost in Toronto in 2026?

For yard drainage, $55 to $95 per linear foot. For full perimeter foundation drain replacement at 7 feet deep, $135 to $210 per linear foot. A typical detached home in Toronto running 130 feet of perimeter falls between $18,000 and $27,000 fully restored.

How deep does a French drain need to be?

A yard drain works at 24 to 36 inches. A foundation drain must reach the bottom of the footing, typically 7 feet for a standard Toronto basement, 9 to 10 feet for an underpinned basement. The pipe always sits below the frost line of 4 feet.

Interior vs exterior French drain, which is cheaper?

Interior is cheaper to install ($80 to $140 per linear foot in Vaughan) but it only manages water once it’s already in your basement. Exterior costs more but stops water at the wall. We recommend exterior when budget allows because it protects the foundation, not just the floor.

Do I need a permit for a French drain in Mississauga?

Surface yard drains, no. Foundation drains tying into the municipal storm or sanitary, yes, through Mississauga’s plumbing permit process, with a separate service connection through the Region of Peel. Budget $400 to $900 for the permits themselves.

How long does a French drain last?

Built right with clear stone, filter fabric, and rigid perforated pipe, an exterior French drain in the GTA lasts 30 to 50 years. Built wrong with sock pipe and no fabric, 8 to 12 years before the perforations clog with silt.

Where does the water actually go?

Three options in the GTA: daylight (downhill to a low spot or ditch), a sump pit with a pump that lifts it to a storm sewer or splash pad, or a gravity tie-in to the municipal storm system. Daylight is cheapest, sump-and-pump is most common, gravity tie-in is best but requires the right elevation.

Does the Toronto basement flooding subsidy actually cover French drain work?

Partially. The 2026 program caps at $6,650 per property and covers backwater valves, sump pumps, battery backup, foundation drain severance, and a plumbing assessment. It does not directly fund full exterior French drain installation, but if your project includes the eligible components, the subsidy can offset $2,000 to $6,650 of the total.

Will a French drain wreck my lawn?

Short term, yes, there’s a trench. Long term, no. We restore with topsoil and sod or seed, and a properly compacted backfill settles less than an inch over the first year. Hardscape like interlock costs more to put back. Budget $40 to $95 per linear foot for full restoration in Richmond Hill.

Can I install a French drain myself?

A 30-foot yard drain 2 feet deep, sure, if you’re handy and rent a trencher. Anything below 5 feet involves shoring requirements, locate-permitting, and risk of cave-in. Foundation drains aren’t a DIY job. One wrong slope and the whole thing fails.