Stop using water
Toilets, washing machines, showers and faucets can feed an active backup.
Sewage coming up · Service available 24/7
Basement sewer backup service
Is dirty water rising from a floor drain, shower or toilet? Stop using the plumbing fixtures and tell us where the backup appears. We direct the intervention according to the affected points, access to the main drain and the contamination risk.
- Emergency service available 24/7
- RBQ 5688-9025-01
- CMMTQ member
- Greater Montreal
Are several fixtures backing up?This helps distinguish a main sewer line problem from an isolated fixture clog.
Keep the area isolated
Keep children and pets away from wastewater and contaminated surfaces.
Avoid electrical hazards
Do not step into water if an outlet or appliance may still be energized.
514 312-1521
Read the symptoms
Is the main drain actually involved?
“Blocked” can describe several different problems. The number of affected fixtures, the floor where they are located and the moment when sewage rises help determine the first checks. An on-site assessment is still required to confirm the cause.
One sink or washbasin only
The blockage may be local to that fixture. See our drain cleaning service.
Several basement fixtures
A floor drain backing up along with a toilet or shower can point toward the main building drain.
Backup during heavy rain
Municipal sewer pressure, inadequate backwater protection or another condition may need to be checked.
Recurring sewer backups
A recurring obstruction or damaged pipe can justify a camera inspection after flow has been restored.
Wastewater and safety
Treat the affected area as contaminated.
A sewer backup is not the same as clean water damage. Plumbing work addresses the cause and restores drainage. Removing materials, disinfecting and drying the building may require a separate specialized restoration service.
If water reaches electrical equipment, do not cross the wet area to switch off the power. Stay away and contact the appropriate emergency service.
Government of Québec guidance for cleaning after a disaster ↗Do not spread contamination
Limit movement between the affected area and clean parts of the building.
Do not handle wastewater unprotected
Official guidance recommends suitable personal protective equipment for cleanup.
Document only when safe
Photos, the highest water level and time of discovery may help with an insurance claim.
Address moisture promptly
Wet or porous materials may require specialized cleaning, drying or removal.
Intervention path
Restore drainage, then determine why it failed.
The immediate priority is to contain the situation and select a useful access point. Detailed inspection comes at the right time, when the line can provide meaningful information.
Describe the backup
Affected fixtures, recurrence, water appearance, recent rain and the water use that triggers the problem.
Locate safe access
Cleanout, floor drain, building drain and access constraints specific to the property.
Clear the line
The method depends on the obstruction, pipe diameter, condition and available access.
Inspect when warranted
A camera can then document roots, an offset joint, a sag or another visible defect.
Select the correction
Targeted maintenance, backwater protection, cleaning or sewer repair based on observed conditions.
Important: hydro jetting and camera inspection are specific services, not automatic steps in every sewer backup call.
Possible causes
One symptom can have very different causes.
Sewage backing up does not identify the cause by itself. The intervention may need to separate one of these conditions from another.
Wipes, grease and debris
Materials that do not break down can narrow or block the passage through the sewer line.
Root intrusion
An opening in the pipe can allow roots to enter and catch other debris.
Sag, offset or damage
Poor slope, a displaced joint or a damaged section can contribute to recurring blockages.
Municipal sewer surcharge
During intense rainfall, pressure in the sewer network can contribute to backups in some buildings.
Backwater protection
A missing, inaccessible, unsuitable or poorly maintained valve may not provide the expected protection.
Isolated fixture blockage
When only one fixture is affected, the obstruction may be in its branch rather than the main sewer line.
Private connection and public sewer
Two parts of the system can require different procedures.
The City of Montréal explains that a sewer connection links a building to the public sewer. The property owner is responsible for maintaining and repairing the entire building sewer connection up to the municipal sewer, including a section that may run beneath public property. Under specific conditions, the City may intervene when a structural problem is located beneath public property.
The official process may require cleaning, a video inspection and a report identifying the defect. When the symptoms may involve the municipal system, or when you need the procedure for your borough, consult the City’s page or contact 311.
Inside the building or private connectionThe plumber checks access, flow and the sewer line to direct the corrective work.
Municipal sewer or defect under public propertyThe City determines its involvement according to its procedure and required documentation.
View Montréal’s official sewer connection repair procedure ↗
After the emergency
Reduce the chance of another backup.
A lasting correction depends on the confirmed cause. A backwater valve may be part of the solution, but its type, location and maintenance must match the building’s drainage system.
Backwater valve service →Keep valves accessible
The City explains how backflow stop valves help prevent sewer backups and recommends checking them regularly, ideally twice a year.
Read the municipal guidance ↗Prepare for heavy rainfall
The City’s building resilience checklist includes working backwater valves on fixtures located below street level.
View the heavy-rain checklist ↗Verify the contractor’s licence
The RBQ’s English page explains how to check a contractor’s licence and the information available in the public registry.
Check an RBQ licence ↗Correct the documented defect
If inspection reveals a structural defect, the pipe may require repair instead of repeated cleaning.
Sewer line and excavation service →Official references
Local and technical information you can verify.
These public resources explain sewer connection responsibility, backup prevention, building resilience and cleanup precautions after contact with wastewater.
Sewer connection repair
Owner responsibilities, required steps, video inspection and procedures that vary by borough.
View the official procedureBackflow stop valves
Valve purpose, location, accessibility and maintenance to reduce sewer backup risk.
Read the municipal guidanceProtection from heavy rain
A practical checklist covering drains, valves and building vulnerabilities during intense rainfall.
Open the building checklistCleaning after a disaster
Personal protection, contaminated materials, drying and precautions for vulnerable people.
Read the cleanup guidanceCustomer experiences
Reviews connected to Plomberie Anjou’s public profile.
Read experiences published by customers. Every backup, access point and sewer line has its own site conditions.
View the Google profile ↗Reviews linked to the public profileRBQ licence displayedCMMTQ member
Frequently asked questions
When sewage backs up.
Direct answers to help recognize the emergency, limit contamination and understand the next checks.
514 312-1521What should I do immediately when sewage backs up in the basement?
Stop using toilets, showers, washing machines and faucets. Isolate the area, keep occupants away and avoid contact with the water. If there may be an electrical hazard, do not cross the wet area. Call and identify which drains or fixtures are backing up.
Why is water coming up through the floor drain?
A floor drain can become an exit point when drainage farther downstream is blocked or under pressure. An obstruction, damaged pipe, roots, inadequate backwater protection or municipal sewer surcharge are among the conditions that may need to be separated.
How can I distinguish a clogged drain from a sewer backup?
One slow or blocked fixture can indicate a local branch problem. When several fixtures on the lowest level gurgle or back up together, the main drain becomes more suspect. An assessment is needed to confirm the actual scope.
Is a sewer camera inspection always required?
No. The line first needs enough flow for the camera to produce useful images. Inspection becomes relevant when the problem recurs, the pipe condition is in question or a visible defect must be documented.
Is hydro jetting always the solution?
No. The method depends on pipe material, diameter, access and condition. A collapsed or broken sewer line cannot be corrected by cleaning alone. The appropriate method is selected after assessment.
Will a backwater valve prevent every sewer backup?
A properly selected and maintained valve can reduce the risk for the fixtures it protects, but its type and location must suit the drainage system. It must also remain accessible for maintenance. The cause of an existing backup still needs separate attention.
Who is responsible for the sewer connection in Montreal?
According to the City, the owner is generally responsible for the building sewer connection up to the municipal sewer, even when part of it runs under public property. The City has a separate procedure for certain structural defects located under public property.
Does plumbing service include cleanup of contaminated materials?
Plumbing work addresses the cause, blockage or sewer line. Water extraction, disinfection, structural drying and removal of contaminated materials may require a separate specialized restoration company.
Is sewage backing up now?
Stop using water and tell us which fixtures or drains are affected.