Why Drains Keep Clogging in Old Toronto Houses

GTA Plumber Match · Updated October 2026

If you live in a 100-year-old semi in the Annex, Leslieville or the Beaches, you probably know the drill: the basement drain backs up, someone snakes it, and six months later it happens again.

Dug-up clay sewer pipe with tree roots growing through a joint — Tree roots grow in through the joints of old clay sewer pipe.

Roots in the clay pipe

A lot of older Toronto homes have a clay sewer lateral running from the house to the street. The joints aren't sealed well, and big street trees send roots into them. Snaking cuts the roots, but they grow back.

Old cast iron soil stack with rust and scale and a cleanout at the base — A cast iron stack in an older Toronto basement, with the cleanout at the bottom.

Cast iron that's closing up

Cast iron stacks rust on the inside. Over decades, the scale narrows the pipe, and everything catches on it.

What actually helps

Camera inspection. It shows whether it's roots, a sag, a break or scale.
Root cutting or hydro-jetting if the pipe is otherwise sound.
Relining or replacing the bad section if it's broken.

Who owns the pipe?

In Toronto, the part of the sewer line on your property is your responsibility. The section under the City's road allowance may be theirs. If roots are on the City side, call 311.

Text us your postal code and what's backing up. We'll match you with a licensed plumber who does drain cleaning and camera inspections, with an upfront flat price before they start.

Why Drains Keep Clogging in Old Toronto Houses

Roots in the clay pipe

Cast iron that's closing up

What actually helps

Who owns the pipe?

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