When the basement is affected
After heavy rain, identify the way water entered
A sewer smell and water rising through a floor drain call for different work than seepage along a foundation wall. A backwater valve is meant to block certain reverse flows through the drain lines it protects. It does not seal a foundation crack or repair a leaking supply pipe. Identifying the entry point prevents an unsuitable repair.
The City of Longueuil recommends checking and maintaining backwater valves. Its heavy-rain guidance notes that debris can interfere with their operation. If your home has a valve, keep its access clear of stored items and new flooring. An appropriate inspection can identify the device already installed and which fixtures it protects.
Record where water rose
Say whether it appeared at a floor drain, toilet, sink or floor joint. A photo before cleanup can preserve useful evidence if it can be taken without contact with wastewater or electrical hazards. Do not resume using fixtures connected to the affected area until it has been assessed.
Keep inspection points accessible
A cleanout, backwater valve and exposed piping give the plumber useful reference points. If the basement has been finished, identify access panels and hidden sections. The location of any new valve depends on the actual drain layout and applicable requirements, not on a neighbour’s installation.
Separate prevention from repair
An inspection after an incident may find maintenance to do, a blockage to clear or an issue requiring another trade. Sewer backup service starts with safety and the likely entry route. Then the appropriate measure can be discussed for that building, without assuming every wet basement has the same cause.