A single run French drain in the Fraser Valley typically costs $2,000 to $5,000, and a full yard system with catch basins and long discharge lines runs $5,000 to $10,000 or more. Trench length and depth, the surfaces the trench crosses, and where the water is legally allowed to go set the price. These are indicative market estimates for August 2026, not quotes.
Below is what sits inside those numbers, what makes one yard cost twice its neighbour, and the rule almost nobody checks first: where your yard water is actually allowed to end up.
What does a French drain cost, job by job?
Yard drainage is priced by the metre of trench and the difficulty of the ground, not by the house. The figures below are indicative Fraser Valley market estimates as of August 2026.
| Job | Indicative cost |
|---|---|
| Single run French drain, one wet area, straightforward gravity outlet | $2,000 to $5,000 |
| Multi run yard system with catch basins and long discharge lines | $5,000 to $10,000 or more |
| Re-piping all downspouts into a dedicated solid line | $2,000 to $6,000 |
| Sump pit and pump where there is no gravity outlet | $2,500 to $6,000 |
| Camera inspection of the existing perimeter drain around the house | $300 to $600 |
| Full perimeter drain replacement, a different job entirely | $15,000 to $30,000 |
Two of those rows deserve a flag. A sump appears in yard drainage quotes far more often than homeowners expect, because a trench that cannot fall to a legal outlet is a pond with rocks in it. And the last row is there so you can see the gap: fixing the yard is a fraction of fixing the foundation drainage, which is why the diagnosis matters more than the quote.
Why does one yard cost twice as much as the one next door?
Because the price follows the water, and the water in this valley is not a small amount. Environment and Climate Change Canada’s 1991 to 2020 climate normals for Abbotsford put annual precipitation at 1,504.6 mm, with 233.1 mm falling in November alone against 39.2 mm in July. A yard drainage system is designed for the November number, not the average.
The specific cost drivers:
- Trench length. The single biggest line. A 12 metre run across one soggy area is a different project from 40 metres of interconnected runs feeding a single outlet.
- Trench depth. Depth is set by how deep the wet zone goes and by the elevation of the outlet. Deeper means more spoil, more rock, more machine time and sometimes shoring.
- What the trench crosses. Lawn is cheap. A concrete driveway, a paver patio, a deck on footings or a mature root zone each add cutting, protection and reinstatement.
- The discharge point. A ditch or storm connection at the property line is the cheap case. No gravity fall means a pit, a pump and power.
- Soil and water table. On the valley floor a trench can fill while you dig it, which means pumping to keep the excavation workable.
- Restoration. Sod, planting beds, irrigation lines and fences all cost money to put back, and a quote that ignores restoration is not cheaper, it is incomplete.
Where is your yard water actually allowed to go?
Onto or into your own property, or into a system the city has approved you to use. Not onto the neighbour, and not into a hole you hope will cope.
The BC Building Code sets the baseline. Section 9.14 requires that foundation drains “drain to a sewer, drainage ditch or dry well,” and where a dry well is used it may only be located where the natural groundwater level is below the bottom of the dry well, and must sit at least 5 m from the building foundation with drainage running away from the house. Section 9.14.6 adds the rule that governs most soggy yards: the site must be graded so that water will not accumulate at or near the building, and a catch basin is required where driveway runoff is likely to reach a garage. You can read the full section in the free BC Building Code text of Section 9.14, Drainage, and those requirements carry into the 2024 edition, which came into effect on March 8, 2024.
Then the municipality adds its own layer, and Abbotsford’s is the strictest in the valley. The City’s stormwater guidance states that stormwater originating within private property “must be managed on-site or directed to an approved stormwater management system,” and that managing it on site means directing runoff to places it can infiltrate, “such as rock-pits, French drains or other infiltration systems.” The same page tells owners to hire a Qualified Professional to run a percolation test and produce a signed and sealed report, says an existing storm connection cannot be reused on a rebuild unless the QP proves the property cannot infiltrate, and sets the design target for a private on-site system at a 1 in 100 year rainfall event. It also puts maintenance squarely on the owner.
That last detail is the one that changes budgets. A rock pit sized for a 1 in 100 year storm is a larger hole than most homeowners picture, and the engineering report is a real line item before a shovel moves.
| Where the water can go | When it works | The catch |
|---|---|---|
| Municipal storm connection | A main fronts the property and the elevation allows gravity flow | Permit and connection fees apply, and the Township of Langley does not permit pumped connections for existing buildings that cannot reach the system by gravity |
| Roadside ditch | Rural and semi-rural streets across the valley | The code names a drainage ditch as an acceptable destination, but the outfall has to stay clear and stay yours to maintain |
| Dry well or rock pit on your own lot | Soil that genuinely infiltrates | Only where the natural groundwater level is below the bottom of the well, at least 5 m from the foundation, and in Abbotsford designed by a QP for a 1 in 100 year event |
| Daylight outlet to a lower part of your property | Sloped lots with real fall | Never onto the neighbour’s land, and the outlet needs an annual clearing |
| Sump and pump | No gravity outlet exists | Adds $2,500 to $6,000 plus power, and city rules on pumped connections differ |
Is a French drain your fix, or do you have a perimeter drain problem?
Match the drain to where the water is coming from. Surface water gets a French drain. Water arriving at the footing gets a look at the perimeter system first.
The quick test: walk the property during real rain. If you can see water sheeting off a slope, a driveway or a neighbour’s higher lot and pooling somewhere, that is a surface problem and yard drainage is aimed at it. If the yard looks fine and the basement or crawl space is still wet, the problem is below ground and a drain camera inspection at $300 to $600 is the honest first spend. Our guide on water in the same basement corner every winter walks through what that pattern usually means.
Roof water sits in between. The Township of Langley warns that downpipes connected to a hole near the foundation are likely tied into the perimeter drains and “can cause excessive flow to your foundation drains and result in flooding of your house.” The BC Building Code’s downspout rule is blunt too: where downspouts are not connected to a sewer, extensions must carry rainwater away from the building in a way that prevents soil erosion. Sorting out downspout and drainage connections is often cheaper than any trench and should be settled before a yard system is designed around the wrong volume of water.
What separates a French drain that works from one that silts up?
Six details, and none of them are the pipe.
- Washed drain rock, not pit run. The code’s own benchmark for foundation drainage granular is coarse clean material with not more than 10 percent passing a 4 mm sieve. Cheap rock full of fines silts the voids in a few seasons.
- Filter fabric wrapping the rock, so soil cannot migrate into it from the sides or the top.
- Continuous fall to the outlet. A flat run holds water and grows biofilm. Slope is what makes a trench a drain.
- A real, legal outlet that stays clear: a ditch, an approved connection, or a properly sited infiltration facility.
- Depth below the wet zone, not a shallow scratch under the sod.
- Cleanouts and an accessible outlet so the system can be inspected and flushed later.
An annual look at the outlet before storm season costs nothing and prevents the most common failure we see, which is a discharge point quietly buried under a season of mulch and leaves.
The short version
Budget $2,000 to $5,000 for a single run and $5,000 to $10,000 or more for a full yard system, then add the discharge solution if gravity is not available. Before any of that, be sure you are fixing the right water: yard drainage handles what runs across the surface, and the perimeter system around the house handles what moves down through the soil against your foundation.
Sorting out a yard that never dries? Call (604) 800-7217, or read what French drains and yard drainage involve and what perimeter drain replacement is for. We work across Abbotsford, Chilliwack, Mission and Langley.
Frequently Asked Questions
How much does a French drain cost in the Fraser Valley?
A single run drain across one wet area typically lands between $2,000 and $5,000, and a multi run yard system with catch basins and a long discharge line usually runs $5,000 to $10,000 or more. Trench length and depth, the surfaces the trench has to cross, and where the water is allowed to end up are the three variables that move the number most. These are indicative market estimates for August 2026, not quotes.
Is a French drain the same thing as a perimeter drain?
No. A perimeter drain sits at the footing of your foundation and protects the house. A French drain is cut across the path water takes through your yard and protects the yard, the driveway or a low spot. They use similar materials, but replacing a failed perimeter drain is a $15,000 to $30,000 excavation around the whole house, while a French drain is a targeted trench where the water is.
Can I just dig a French drain myself?
You can, and the ones that fail usually fail for the same three reasons: the wrong rock, no filter fabric, and no real outlet. Fine material washes into the voids and the trench silts up, or the pipe has nowhere to fall to, so it fills and stays full. If the trench cannot reach a legal discharge point by gravity, a DIY trench becomes an underground pond.
Do I need a permit for a French drain in Abbotsford or Chilliwack?
Work entirely inside your own property that infiltrates on site is treated differently from work that connects to the city storm system, and connecting always involves the city. Abbotsford requires a Qualified Professional to assess whether your soil can infiltrate before a storm connection is considered, and Chilliwack requires a Service Connection Permit before any storm drain is connected. Confirm your specific job with the municipal engineering desk before you dig.
Will a French drain fix water in my basement?
Sometimes, and only when the water reaching the foundation is surface water from a slope, a driveway or a low yard. If water is arriving at the footing because the perimeter drain around the house is silted or collapsed, a yard drain upstream will reduce the load but not fix the failure. A camera inspection of the existing perimeter drain, $300 to $600, is what separates those two cases.
How long does a French drain last?
A properly built system, washed drain rock, filter fabric on all sides, continuous slope and a maintained outlet, commonly gives decades of service. The failure mode is almost never the pipe. It is silt filling the rock voids or an outlet that has been buried, blocked or landscaped over, which is why the discharge end deserves an annual look before storm season.
Published August 20, 2026 · Last updated August 20, 2026 · Fraser Valley Drainage