Guide · Sewer & main drain
When Tree Roots Find the Sewer Lateral
Tree roots push through the joints of old clay and cast iron sewers, then fill the pipe with a mat that catches paper and grease. Here is how a rooted lateral shows itself and how it gets cut, inspected and repaired.
- A plumber answers when you call
- Clear price before any pipe is cut
- Basements left as clean as we found them
The Markham angle
Every house drains through a private sewer lateral that runs from the basement, under the front yard, to the municipal main. In older neighbourhoods such as Thornhill, Royal Orchard, German Mills and the historic cores of Unionville and Markham Village, those laterals were often made of clay tile or early pipe with many joints. Decades later, trees planted around the same time have grown huge root systems.
Roots go looking for water and nutrients. A sewer joint with even a hairline gap releases warm, moist air, and a fine root finds its way in. Inside, it thrives, grows into a mat and catches paper and grease until the line slows or stops.
Signs to watch for
- Several drains slow at once, especially the lowest ones in the basement.
- Gurgling in a toilet when the washing machine drains.
- Water rising from the floor drain after heavy use upstairs.
- Blockages that come back every year or two, often in the same season.
- Unusually lush patches of lawn over the sewer route.
One step after another
- Clear the line. A plumber uses a cable machine with a cutting head, or a high-pressure jetter, to open the pipe from the cleanout.
- Look inside. A camera inspection records where roots enter, how bad the joints are and whether the pipe has cracked, sagged or shifted.
- Decide on a plan. Light root intrusion in sound pipe can be managed with periodic clearing. Broken, collapsed or badly offset pipe usually needs repair.
- Consider repair options. Depending on the damage, the fix may be a spot repair, a full lateral replacement, or a trenchless method where conditions allow.
- Talk to the city about the boundary. The City of Markham can explain responsibilities when roots or damage are near the property line or the city portion of the connection.
Slip-ups we see often
- Pouring root-killing products down the drain without a diagnosis. They may slow growth but do nothing for cracked or sagging pipe.
- Removing a healthy tree out of fear. Many trees and laterals coexist for years with routine maintenance, and city trees are protected in any case.
- Planting willows, poplars or silver maples near the sewer route. Their roots are especially aggressive.
- Clearing the line every few months without ever looking inside it.
Time to pick up the phone
Call if you see the signs above, or immediately if sewage backs up into the basement. We offer main sewer line clearing, camera inspections and sewer line repair. After a clearing, a backwater valve can add protection against storm backups from the street.
Light root intrusion in sound pipe can be managed with periodic clearing.
From the job notes of Plumbers in Markham
Guide · Sewer & main drain
Signs to watch for
- Toilets bubble or rise when a tub drains
- A sewer odour rising around the basement floor drain
Call a plumber when
- Water is reaching a ceiling, wall cavity or electrical panel
- Sewage is coming up through a floor drain or toilet
- You smell gas near the water heater: leave and call the gas utility first
- A valve will not close or a fitting keeps weeping after tightening
Markham note. Markham Village and Unionville still have clay sewer laterals under mature maples, and those roots are behind many of our spring and fall main-line calls. The City of Markham has offered help for parts of the lateral in the right of way; check current terms before digging.