Water in Your Montréal Basement: Backwater Valve, Retention Pit or French Drain?
Foundation repair, French drain, excavation
Marco comes to you in person for every estimate. Reachable 7 days a week, 8 a.m. to 5 p.m.
Water in Your Montréal Basement: Backwater Valve, Retention Pit or French Drain?
Foundation repair, French drain, excavation
Marco comes to you in person for every estimate. Reachable 7 days a week, 8 a.m. to 5 p.m.
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Get your free estimateIn a city of 19 boroughs, three water protections not to be confused
The Process
Interior
Crack repair
Exterior
Crack repair
What the City of Montréal requires to protect a basement
- Backwater valves. If your basement has already flooded or had a sewer backup, a valve on each plumbing fixture is mandatory under the municipal bylaw. Since 2011, they are required in all new buildings. They must remain accessible, and the City recommends checking them ideally twice a year.
- Retention pit. It goes inside the home, with minimum dimensions of 600 x 450 x 450 mm (24 x 18 x 18 in.), a pump to prevent overflows, a valve, and ideally battery backup, since a power outage sometimes comes with violent storms.
- Gutters. Gutter water (or the overflow of a rain barrel) must be directed to a permeable surface, such as a flower bed or the lawn, at least 1.5 m from the foundations. Connecting a gutter to the foundation drain, aiming it at an impermeable surface or at the street is prohibited, and fines apply.
- Work and certificate. The City advises hiring a plumbing contractor who is a member of the CMMTQ for valves and the pit, and asking for a certificate of conformity with the invoice.
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Questions about drainage and foundations in Montréal
My Montréal basement has flooded before: is a backwater valve mandatory?
Yes. According to the City of Montréal, if you have already been flooded or had a sewer backup, installing valves on each plumbing fixture is mandatory under the municipal bylaw. Since 2011, valves must also be installed in all new buildings.
What is the minimum size of a retention pit in Montréal?
The City gives minimum dimensions of 600 x 450 x 450 mm (24 x 18 x 18 in.), inside the home. It recommends fitting a pump to prevent overflows, a valve to keep wastewater from backing up and, ideally, battery backup.
Where should I direct my gutter water in Montréal?
To a permeable surface, such as a flower bed or the lawn, at least 1.5 m from your foundations. Connecting a gutter to the foundation drain, aiming it at an impermeable surface or at the street is prohibited, and the regulation comes with fines.
Does a backwater valve also fix water coming in through my foundation?
No. The valve keeps wastewater from backing up through the plumbing. Water that comes in through a wall, a crack or the slab is a different problem, which calls for a diagnosis of the foundation and the drainage. Read 4 Kinds of Water Damage That Threaten a Quebec Home’s Foundation.
Is there financial help in Montréal to protect my building?
Yes. The City’s RénoPlex program can subsidize flood-protection work of $500 or more for a house or a building of 5 units or fewer, subject to a maximum property value. Conditions change: read our article how to finance foundation repairs in Quebec and check the program before starting work.
Who assesses my foundation in Montréal, and how do I book?
Marco comes himself for the free estimate. Fill out the form on this page or call (438) 763-0737 between 8 a.m. and 5 p.m., Monday to Sunday. His company holds RBQ license No. 5775-3246-01.
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