For a typical project of 20 m (66 ft) of French drain and 2 downspouts (all of Quebec): $3,761 doing it yourself, $3,000 to $4,600 by a contractor, before tax.
Materials at retail prices, rentals, delivery and disposal, plus your time as a beginner (*).
* Includes your time: 49 h × $35.05/h (beginner). Money spent only: $2,043
Tools to buy, on top: $156
Labour, equipment, materials, overhead and margin.
Crew pace: 11 person-hours
Stacked extremes (everything low, everything high): $2,375 to $6,547
The range shows the effect of documented price and productivity spreads. It is not a probability.
At $35/h: the two options come out about even.
Break-even = (the contractor's typical price minus the money spent doing it yourself) divided by your person-hours. Before tax on both sides: GST and QST apply to both.
| Measure | Beginner | Intermediate |
|---|---|---|
| Money spent | $2,043 | $2,043 |
| Person-hours | 49 h | 33 h |
| Days of 8 h, 2 people | 3.5 days | 2.5 days |
| Your time at $35/h | $1,718 | $1,169 |
| True cost | $3,761 | $3,212 |
Working days only: add rain days and waiting times (curing, deliveries).
Before tax, one scale for every bar.
| Money, do it yourself | $2,043 |
|---|---|
| True cost, beginner | $3,761 |
| True cost, intermediate | $3,212 |
| Contractor | $3,000 to $4,600 ($3,800) |
| Materials | 16% | $584 |
|---|---|---|
| Labour | 13% | $485 |
| Equipment and rentals | 18% | $679 |
| Delivery and disposal | 17% | $625 |
| Overhead | 27% | $1,017 |
| Margin | 10% | $377 |
The range shows the effect of documented price and productivity spreads. It is not a probability.
Intermediate
Hours for the typical project: the work calculation (a crew's pace times the level's factor, with rework, learning and unloading) plus the guide's planning and checks.
Before digging a drain, watch where water runs during a heavy rain and where it sits. Often it is enough to extend the downspouts away from the foundation and give the ground a slope that takes water away from the house.
A yard drain, a French drain or a swale on your land is not plumbing under the Construction Code: the plumbing chapter excludes piping not attached to a building and foundation drains. A connection to the building drain or the municipal sewer needs a plumber and, generally, a permit. Municipalities also have their own rules on downspouts and rainwater. Before you dig, file your Info-Excavation request.
A French drain is a trench somewhat wider than the pipe, deep enough to hold a stone bed, the pipe and a stone cover. Its bottom must fall continuously toward the outlet: at least 1%, never less than 0.5%. A dip or a back-fall holds water and eventually clogs the drain. The calculator gives the width, the volume to dig and the spoil.
Geotextile lines the trench so fine soil cannot clog the stone. The perforated drain sits on a bed of clear stone, gets covered with stone, then the fabric is closed over the top. Check the fall of the pipe itself, not only the bottom's. The calculator gives the tonnes of stone, the square metres of fabric and the pipe length.
Above the fabric, backfill with site soil and reshape the surface so water heads to the swale or the outlet rather than the house. Downspouts are extended away from the foundation and discharge onto a surface that absorbs, never into the foundation drain. A catch basin goes at the low spot, its grate slightly below the surrounding ground, and connects through a sloped solid pipe. A dry well needs soil that absorbs: do an infiltration test before building it.
Lower land receives the natural flow of water from higher land, but the upper owner may not make the neighbour's situation worse (Civil Code of Quebec, art. 979). Do not aim your downspouts, drains or slopes at the neighbouring lot.
Gouvernement du QuébecLégisQuébec, Éditeur officiel du QuébecChecked October 10, 2026
Yard drains, French drains and swales not connected to a building, as well as foundation drains, are excluded from the Construction Code's plumbing chapter. A connection to the building drain or the municipal sewer belongs to a plumber who is a CMMTQ member (interpretation, to confirm with your municipality).
LégisQuébec, Éditeur officiel du QuébecRégie du bâtiment du QuébecChecked October 10, 2026
Quebec City: increases in impervious area refer to the stormwater management sheets; near water and steep slopes, special rules apply; slopes are limited to 50% and 3 m high.
Ville de QuébecChecked October 10, 2026
Saint-Rémi: the explanatory document on rainwater management asks for a 10% slope over the first 1.8 m around the house, and about 2% toward the street. An example of a local drainage rule.
Ville de Saint-RémiChecked October 10, 2026
Never go into a trench deeper than 1.2 m unless its walls are shored or sloped back. Keep soil and materials at least 1.2 m from the edge and machines at least 3 m back. These rules bind employers; the danger is the same for a homeowner.
Gouvernement du Québec (LégisQuébec)Checked October 10, 2026
Before digging, file a free Info-Excavation request at least 4 business days ahead; it is valid 180 days at most.
Régie du bâtiment du QuébecChecked October 10, 2026
Locating underground networks is free and requested before digging. The requester's name and the ticket number should be on file.
The slope, the outlet and what happens at the property line. You may not make runoff onto the neighbour worse.
The quantity in cubic metres or tonnes, and whether hauling and disposal are in the price.
Clear stone, topsoil, fill: the material's name and the thickness in millimetres.
Lawn, driveway, beds damaged by machinery: included or not.
For sod take, the drain working, or fill settling.
In every case: an RBQ licence when the work requires one, a business number (NEQ), civil liability insurance and a written contract.
Guide: choosing a contractorDraft: this content has not yet been reviewed by an installer or an engineer. The numbers come from the engine; the explanations may still change.