Tree roots in the sewer line: the signs to watch for
Tree roots are the most common cause of recurring sewer back-ups we see across Southern and Central Ontario. They rarely show up overnight. The warning signs build for months, and most homeowners notice at least one of them long before the basement floor drain overflows.
Roots go looking for water and nutrients, and a sewer lateral carrying warm wastewater is the richest source on most properties. Once a hair-thin root finds a loose joint or a crack, it grows inside the pipe, catches paper and grease, and slowly narrows the line until water has nowhere to go.
The signs to watch for
- ✓Gurgling from toilets or the floor drain when a tub empties
- ✓Several fixtures draining slowly at the same time
- ✓Toilets that clog often, even with nothing unusual flushed
- ✓A soggy, greener patch of lawn above the sewer line
- ✓A sewage smell near the floor drain or cleanout
- ✓Back-ups that return weeks after the line was snaked
One slow sink is usually a local clog. Several fixtures slowing together, especially the lowest drains in the house, points to the main line. That is where roots tend to live.
How roots get in
Older homes with clay or cast iron laterals are most at risk. Clay pipe was laid in short sections with mortar or gasket joints, and every joint is an opening. Cast iron corrodes and cracks with age. Even newer PVC lines can be invaded where a joint has shifted from frost heave or settling soil.
Willows, silver maples and poplars are the usual suspects, but any mature tree within about fifteen metres of the line can reach it.
When a camera inspection is worth it
If you have had the line cleared more than once in two years, book a camera inspection before the next clearing. We run a camera from the cleanout to the city connection, record the footage and show you exactly where the roots are entering, how far along the pipe the damage runs and whether the pipe itself is still sound.
That footage decides the fix. Light intrusion at one joint can often be handled with a spot repair. Heavy roots along a cracked clay line usually means relining or replacing the lateral, and you will see the reason on screen before you approve the price.
