Your main sewer line carries all the wastewater from your property to the municipal network. When this line gets clogged, the consequences can be serious and costly. In Montreal, where aging systems and winter conditions create unique challenges, recognizing the signs of a blockage can save you thousands of dollars in emergency repairs.
As drainage specialists in Montreal for over two decades, we've seen countless situations where early intervention could have prevented major damage. Here are the five telltale signs that it's time to call a professional.
The 5 Warning Signs
Emergency Signal
If you observe several of these signs simultaneously, contact a certified plumber immediately . A complete blockage can occur quickly and cause major water damage.
1. Multiple Sewer Backups in the House
The most obvious sign of a main sewer line problem is when multiple plumbing fixtures back up simultaneously . If you flush the upstairs toilet and water comes back up in the basement shower, that's a major warning sign.
Unlike a single clogged drain that only affects one fixture, a blockage in the main line impacts the entire system. You might notice that water drains poorly in several places at the same time, or that using one fixture causes a backup elsewhere.
Montreal Regulation
City of Montreal By-law 11-010 requires the installation of backwater valves to protect properties against sewer backups. If you don't have this device and live in a risk area, your vulnerability is increased.
2. Persistent Gurgling Sounds in the Drains
Do you hear gurgling sounds coming from your toilets, sinks or floor drains when you're not using the plumbing? These strange sounds are often the first warning of a blockage developing in your main sewer line.
Gurgling occurs when air trapped in the pipes seeks to escape. In a properly functioning system, air escapes through the plumbing vents that run through your roof. But when a blockage forms, air looks for other exits, creating these characteristic bubbles and sounds.
3. Drains That Empty Abnormally Slowly Everywhere
A single slow drain may indicate a localized blockage. But when all your drains empty slowly at the same time , it's almost certainly your main sewer line that's compromised.
In Montreal, aging cast iron sewer lines are particularly vulnerable. Many homes built before 1970 still have their original cast iron pipes, which can develop rust, cracks and failing joints after decades of use.
Never Use Harsh Chemical Products
Commercial cleaners can further damage already weakened pipes and will not resolve a main line blockage. A professional hydro jetting cleaning is the appropriate solution.
4. Sewer Odors in the House or Yard
Sewer odors should never be present in a home with functional plumbing. If you smell hydrogen sulfide (rotten egg smell) coming from your drains, basement or yard, your main sewer line could be cracked or partially blocked .
A partial blockage can prevent sewer gases from properly escaping through the roof vents, forcing them to rise through the drains. These gases are not only unpleasant, they can be dangerous to your health.
5. Lush Vegetation or Unexplained Wet Areas in the Yard
Have you noticed a section of your lawn that's surprisingly green and lush compared to the rest, even during dry periods? Or an area that stays constantly wet without apparent reason?
These signs can indicate a leak in your main sewer line. The escaping wastewater acts as a natural fertilizer, creating areas of excessive growth. This is a serious public health and environmental problem.
Need an Urgent Inspection?
Our team of certified plumbers is available 24/7 to diagnose and resolve your sewer line problems in Montreal, Laval and on the North and South Shores.
Call‑us: 514‑829‑7514What to Do If You Recognize These Signs?
If you identify one or more of these signs, don't delay. Main sewer line problems worsen quickly and repairs become exponentially more expensive over time.
- Stop using the plumbing. Minimize water usage in your home to avoid worsening a backup or leak.
- Don't pour chemical products. Commercial cleaners are ineffective against main line blockages and can damage your pipes.
- Contact a certified RBQ/CMMTQ plumber. In Montreal, all plumbing work must be performed by contractors who are members of the CMMTQ and hold a license from the Régie du bâtiment du Québec.
- Request a camera inspection. This technology allows for precise diagnosis of the problem without unnecessary excavation.
Prevention: Your Best Defense
For homes over 25 years old or those with mature trees nearby, a camera inspection every 3 to 5 years can identify problems before they become costly emergencies.
Frequently Asked Questions
Contact AAA Complete Drainage
At AAA Complete Drainage, we offer camera inspection services and professional sewer cleaning to help Montreal homeowners keep their systems in excellent condition.
Don't let a sewer line problem compromise your home and your peace of mind. If you recognize any of these five signs, contact us today for a professional inspection.