⚠️ Active water in your basement? Call for priority service → (514) 730-7107
Published October 12, 2026 · 7 min read · By the Fissure et Drain XT team, RBQ licence 5863-7364-01
Purpose
What a French drain does
A French drain is a perforated pipe laid at the foot of the foundation, outside, in a bed of clean stone. It collects water from the soil before it pushes against the wall and carries it to the sump pit or the storm sewer. When it clogs, water has nowhere to go: it builds up around the foundation and looks for a way in.
A PVC French drain at the foot of the foundation, in clean stone, with the membrane on the wall.
Symptoms
7 signs your drain is clogged
Water at the joint between the wall and the floor of the basement, especially after rain or during the thaw.
A damp basement or a musty smell that keeps coming back, even with no visible damage.
White stains (efflorescence) at the bottom of the foundation walls.
A sump pit that stays dry during heavy rain: the water no longer reaches it.
Orange sludge in the sump pit: a sign of iron ochre.
Cracks that seep when they used to be dry.
A house over 30 or 40 years old with its original drain, especially if it is clay.
Causes
Why a drain clogs
Sediment and roots
Sand and silt get in through the perforations, and tree roots find the water inside the pipe.
Iron ochre
An orange deposit that clogs the drain in a few years in several areas of the North Shore.
Crushed or clay drain
Old clay drains crack and shift out of line. A crushed pipe no longer lets water through.
Poor installation
A bad slope, missing clean stone or the wrong filter fabric make the drain clog faster.
Diagnosis
Clean or replace? The camera decides
A drain clogged by deposits but otherwise in good shape can often be cleaned: when that is the right fix, we flush it with high-pressure water instead of replacing it. A crushed, cracked or clay drain has to be replaced. There is no way to tell by eye: only a camera inspection shows the inside of the pipe.
The camera goes in through a cleanout. If there isn’t one, we dig down to the drain to install it, so future inspections and maintenance need no excavation. You keep the video, whether the drain is in good shape or not.
If replacement is needed, our cost guide explains what affects the price. Installation starts at $160 per linear foot for a simple, easy-access job, and can cost considerably more depending on the site.
The cleanouts (vertical white pipes) give access to the drain to inspect and clean it without digging.
Insurance
Is it covered by my insurance?
In Quebec, wear and tear on a French drain is generally considered maintenance: cleaning or replacing it is usually not covered. Water damage in the basement may be, depending on your policy and its endorsements. Check your contract and call your insurer before the work.
For a recently purchased house, a clogged drain can raise the question of a hidden defect. Document everything: photos, inspection video, dates. A lawyer or notary can advise you on your options.
Frequently asked questions
Clogged French drain
How long does a French drain last?
+
A well-installed modern PVC drain normally lasts several decades. Old clay or corrugated drains, and drains affected by iron ochre, often last much less.
Can I unclog a French drain myself?
+
It is not recommended. Without access through a cleanout and without a camera, you don’t know where the blockage is or whether the pipe is crushed. You risk paying for a cleaning that fixes nothing.
Can a clogged drain cause cracks?
+
Water building up against the foundation increases the pressure on the walls and worsens existing cracks, especially with frost. It also makes dry cracks start to seep.
Does the whole drain need to be replaced?
+
Not always. If the camera inspection shows a localized problem, a partial repair may be enough. If the drain is clay or cracked in several places, full replacement lasts longer.
*
The warranty covers only workmanship defects and construction flaws related to the work performed by Fissure et Drain XT. It does not cover damage caused by ground movement, soil defects, earthquakes, exceptional flooding, work done by third parties or any unauthorized modification after the work is completed. Warranty transferable to the new owner upon written notice. RBQ 5863-7364-01.
