Problem guide
Sewer backup: what to do and who to call
Avoid contact with backed-up water, limit fixture use, and describe what is affected before requesting help.
Sewer backup: protect people first
Keep children and pets away from backed-up water or material. Avoid direct contact and do not clean a contaminated area without knowing the required precautions. If water is near an electrical installation, do not enter the area; use the appropriate emergency service.
Stop using fixtures that may add water to the system. Do not pour products into drains or dismantle piping to search for the blockage.
One drain or several fixtures?
Note:
- the drain or fixture where water appears;
- how many drains, toilets, or sinks are affected;
- the colour, odour, and direction of the flow without touching it;
- when the backup started;
- recent work, heavy rain, or changes in the building;
- whether neighbours seem to have a similar issue, only if you can check without entering the risk area.
These observations help prepare the request, but they cannot establish remotely whether the cause is on private property or in the municipal network.
Who should you call?
A major or recurring backup may require a plumber, a municipal check, and a conversation with your insurer. In Longueuil, you can also consult municipal information about the water and sewer network. The selected professional can confirm what should be inspected and in what order.
Share your municipality, affected fixtures, and urgency. See the sewer backup service page to request a match.
Official safety reference
Protect your home and property in case of flooding — Gouvernement du Québec