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Main sewer line cleaning

Main Sewer Line Unclogging in Montreal

Slow drains, recurring backups or sewer odors can point to buildup in the main sewer line. When the main line is blocked, water from sinks, toilets, showers or laundry can come back up through the lowest drain or fixture.

If water is backing up right now, stop using water and call. We provide immediate intervention for active main-line backups, and planned sewer cleaning for recurring roots, wipes, grease or cast iron buildup.
  • 🛡️
    Cast iron drain cleaning Cleaning can help improve flow when rough cast iron buildup keeps catching debris.
  • 🤝
    Roots and recurring backups Repeated slowdowns can point to roots, wipes, grease or buildup inside the main line.
  • 🚨
    Immediate help for active backups If wastewater is coming up through a floor drain, toilet, shower or basement drain, stop using water and call.
Truck and cleaning equipment set up before a main sewer line intervention

Customer Testimonial

N
Nathan
February 2025
★★★★★

"I can't say enough good things about the incredible service I received from Scott! He came the same day I called, which was such a relief. Scott went above and beyond to unclog my stubborn bathtub drain, expertly fixed my shower, and even identified a sink issue that wasn't up to code—something I wouldn't have known about otherwise. His professionalism, efficiency, and attention to detail were top-notch. He took the time to explain everything clearly and left my home spotless after completing the work. If you're looking for a reliable, knowledgeable, and thorough plumber, I highly recommend Scott! Fantastic experience from start to finish."

✓ See full review on Google

What Causes a Main Sewer Line to Block

Your main sewer line carries wastewater from the whole house. These are the problems that most often lead to slow drains, recurring backups or active wastewater backup.

"Flushable" Wipes (Baby Wipes)

Unlike toilet paper, wipes do not break down well and can collect inside the main line. One of the worst things you can do for your drain is flush wipes down your toilet (WC). This can cause major backups that may require our emergency drain service.

Root Intrusion

Roots seek moisture and can enter through joints or small openings. Once inside, they catch grease, wipes and paper until the same line starts backing up again.

Sewer Backup (Blocked Pipe)

Water coming up through a floor drain, shower, toilet or basement drain can mean the main line is blocked. Stop using water and call. If the basement is flooding or the backup cannot wait, use our emergency drain service page.

The Scourge of "Flushable" Wipes

Flushable wipes block sewer lines

Flushable wipes are one of the most common causes of sewer blockages. Even wipes labeled "flushable" do not break down like toilet paper.

  • Why they're destructive: Unlike toilet paper that breaks down in less than 60 seconds, wipes are made of plastic fibers that stay intact for years. They accumulate and create impenetrable dams.
  • Montreal's "Fatbergs": Municipal crews regularly remove tons of these masses of wipes and grease. Your residential sewer is just as vulnerable to these costly blockages.

The Golden Rule

Only 3 things should go in the toilet: urine, feces and toilet paper. Everything else — even products labeled "flushable" — belongs in the trash.

Truck and cleaning equipment set up before a main sewer line intervention

The Silent Invasion of Roots

Tree roots are programmed to seek water. Your sewer line is their ideal target — moist, nutrient-rich and accessible.

How roots penetrate your pipes

Even a microscopic crack or slightly loose joint is enough. Rootlets infiltrate through these openings, then grow inside the pipe. A root the size of a hair can become a mass the size of a football in a few years.

Signs of root intrusion

  • Slowing: Drains that gradually slow down over months
  • Sounds: Recurring gurgling noises
  • Seasonal: Backups that worsen in spring (growing season)
  • Exterior: Abnormally green lawn areas above the pipe
  • Ground: Ground settling near the house

Managing recurring root problems

Roots can enter through joints or small openings and catch debris moving through the line. If the same line backs up repeatedly, roots may be part of the problem.

Roots invading a main sewer pipe during an inspection

Older Homes & Cast Iron Drains

Cast iron is strong, durable and quiet

That is why it is still a solid choice for vertical stacks, especially in duplexes, triplexes and multi-unit buildings where pipe noise matters.

The downside is age. Over time, rust and mineral buildup, called tuberculation, can form inside cast iron drains. It narrows the pipe and creates a rough, Velcro-like surface that catches wipes, grease, paper and debris.

  • The Cycle: You pay to unclog the same drain every 6 months because the jagged surface remains.
  • The Risk: If ignored, tuberculation leads to Channel Rot—where the bottom of the pipe rusts away completely, completely destroying the pipe.

Managing Cast Iron Buildup

Stop the cycle of temporary fixes.
For recurring cast iron problems, a camera inspection is recommended to understand the pipe condition and whether descaling, cleaning or another service is needed to bring the drain back to good health.

The 10 Worst Things For Your Drain

Avoid these items to protect your drainage system and avoid costly repairs.

  1. 1. Wet wipes: They do not break down like toilet paper and can collect inside the main line.
  2. 2. Grease and oils: Liquid when hot, they solidify in your pipes and catch everything else.
  3. 3. Hair: It tangles with soap to form rubbery clogs. Use drain screens in showers.
  4. 4. Hygiene products: Tampons and pads absorb water, swell and can create fast blockages.
  5. 5. Cotton swabs / Floss: They do not break down and can cling to rough spots in the line.
  6. 6. Coffee grounds: Grounds can accumulate and form a dense paste that obstructs pipes.
  7. 7. Rice and pasta: They continue to swell in water and can create sticky masses in drains.
  8. 8. Cat litter: It clumps on contact with water, which is exactly what you do not want in a drain.
  9. 9. Paint / Chemicals: These products can damage pipes and contaminate the water system.
  10. 10. Medications: They do not usually block drains, but they contaminate water. Return them to the pharmacy.

Already too late?

If you've put these items down your drains and notice flow problems, call us before the blockage gets worse. If water is backing up right now, stop using water and call.

How We Unblock the Main Sewer Line

We clean the main sewer line based on the symptoms, access point and type of buildup, then test the flow and explain what was found.

Assessment and access

We review the symptoms, locate the available access point and explain the work before starting.

Main-line cleaning

The cleaning approach depends on access, pipe condition and the type of buildup. The goal is to restore proper drainage without making the tool the main selling point.

Flow test and recommendations

We test drainage flow and explain what was found. If the problem keeps returning, a camera inspection may be recommended to check pipe condition.

Roots extracted from a sewer pipe after mechanical cleaning

Main Sewer Line Unclogging Service Areas

Sewer cleaning and active main-line backup help are available in Montreal, Laval, Longueuil and the South Shore.

Service in your area

Call or text with the symptoms, the affected drains and whether water is backing up right now. We will confirm the service area and explain the next step before the work starts.

Montreal and boroughs

Main sewer line cleaning for slow drains, recurring backups and active wastewater backups across Montreal.

Laval

Sewer cleaning help for homes dealing with roots, wipes, grease buildup or active main-line backup.

Longueuil and South Shore

Service for planned sewer cleaning and urgent main-line backup problems on the South Shore.

Price for a Blocked Main Sewer Line

The price is explained before the work starts, with no hidden charges.

Price depends on access and buildup

The exact price depends on whether the call is an active backup or planned cleaning, the access point, the line condition, the type of buildup and the work needed. It is confirmed before the work starts.

To explain your situation and confirm the price before the work, call 514-829-7514 or text 514-829-7514.

Frequently Asked Questions

The exact price depends on whether the call is an active backup or planned cleaning, the access point, the line condition, the type of buildup and the work needed. The price is confirmed before the work starts, with no hidden charges.

Stop using sinks, toilets, showers, dishwasher and washing machine until the line is checked. If the basement is flooding or wastewater is coming up through a floor drain, call now and use the emergency drain service page.

Warning signs include slow drains in more than one fixture, gurgling sounds, recurring sewer odors, wastewater coming up through the lowest drain or backups that return after a short time.

Yes. Roots can enter through joints or small openings and catch debris moving through the line. If the same line backs up repeatedly, roots may be part of the problem.

Yes. Cleaning can help improve flow by reducing buildup that catches debris inside rough cast iron pipe. If the problem keeps returning, inspection may be recommended to understand pipe condition.

No. Hydro-jetting is not currently offered. This sewer cleaning page does not market that service.

Main Sewer Still Backing Up? Call Now

For planned sewer cleaning or active main-line backup, call before the blockage gets worse.