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PlomberieBoucherville

Backwater valves: installation, inspection and compliance

A backwater valve is the only plumbing component that protects your basement when the municipal network overflows. It lets water out and stops it coming back.

On the South Shore this is not optional: Boucherville, Chambly, Carignan, Saint-Basile-le-Grand, Saint-Mathieu-de-Beloeil and La Prairie require one by by-law, Beloeil since 1961, and Contrecœur goes as far as subsidising it. Several of those by-laws state that without a compliant, maintained valve the City is not liable for the damage.

We install them, we inspect them, and we will tell you plainly whether the one you already have is still doing its job.

Does this sound familiar?

  • Your basement has already backed up, even once
  • You do not know whether the house has a valve, or where it is
  • The valve is inaccessible — set in the slab or closed behind finishing
  • It has never been opened or cleaned since you bought the house
  • Your municipality requires one and you have no proof of compliance
  • You have plumbing fixtures below street level

How we work

  1. We check what is already there

    Many homes have a valve nobody has ever opened. We locate it and check whether the flap moves freely and the seat still seals.

  2. We read your town's by-law

    Requirements vary between municipalities: permitted valve type, placement, whether a pump is required. We install to your by-law, not to a general rule.

  3. We install on a secondary line

    Never directly in a floor-drain outlet, never on the building drain — both placements are explicitly prohibited by several South Shore by-laws.

  4. We leave it accessible

    A valve you cannot open cannot be maintained, and several by-laws require annual owner maintenance. Access is part of the installation.

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Describe your project and we will come back to you with next steps.

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Frequently asked questions

Is a backwater valve mandatory where I live?
In several South Shore towns, yes. Boucherville requires one “whatever the year of construction of the building”, Carignan likewise, Beloeil since 1961, and La Prairie additionally requires a submersible pump. See your city's page for the by-law that applies to you.
Is there a subsidy?
In Contrecœur, yes: the City offers a subsidy of up to $500 for the purchase and installation of a valve, for homes built before 1 January 2000. Confirm the conditions with the City before the work.
Is a plug in the floor drain equivalent?
No. The Saint-Mathieu-de-Beloeil by-law says so explicitly: “Using a threaded plug to close a floor-drain opening is permitted but does not constitute a retention valve within the meaning of this by-law.” Capping the drain makes no one compliant.
How often does it need servicing?
At least once a year. Boucherville's by-law requires valves to be “accessible, kept in good working order and serviced at least annually by the owner”. A flap jammed with debris no longer protects anything.

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