Blocked drain Paddington: tree roots

Adam was at this Paddington strata block for a different job: replacing the building's old cast iron stack. Working in the narrow side passage along the building, he took a look at the drain opening at the base of the wall. It turned out to be a blocked drain in the making, full of tree roots that nobody in the building knew were there.

That is often how root problems get found in strata buildings. The drain is out of sight in a side passage or courtyard, it still more or less works, and nobody thinks about it until something backs up. Having a plumber already on site for other work is a good chance to check it.

What was blocking the drain

Not a few stray strands. A dense, matted mass of live root had grown inside the pipe, the kind that only builds up over time. Everything that went down that drain had to squeeze past it.

Roots go looking for drains because a drain holds exactly what they need: water, nutrients and air. A hairline gap at an old pipe joint is all it takes for a fine root to get in. Once inside, it spreads into a net that catches everything passing through, so the drain slows, partly clears, and slows again.

Clearing a tree root blocked drain with a jetter

Adam cleared the line with a high-pressure water jetter. The jetter cuts the roots out and scours the pipe wall, rather than just poking a hole through the middle. The root mass came back out through the opening in the side passage, and what you see in the photo above is what had been living in the drain.

A plunger or a hand snake would not have fixed this. They can punch a channel through a root ball and get water moving for a little while, but the live root stays in the pipe and keeps growing, so the drain blocks again. For more on why this keeps happening in older buildings, read: Tree roots in old clay drains: the Eastern Suburbs problem that never goes away.

Why Paddington drains get tree roots

Paddington is best known for its Victorian terraces, but the suburb also has plenty of brick unit blocks, and both sit on drainage that has been in the ground for decades. Much of it is original clay or earthenware pipe with joints that dry out and crack with age. Add the established street trees and leafy gardens Paddington is known for, and roots have both the reason and the way in.

Dry spells make it worse. When it has not rained for a while, the moisture inside a drain is the most reliable water source around, and roots head straight for it.

Stacks and drains in older strata buildings

The job that brought Adam here is common in buildings of this age. Cast iron stacks were standard in Sydney unit blocks for decades, and many are now reaching the end of their life. We wrote up a similar job in Strata waste stack replacement, Coogee. The drains those stacks empty into are usually just as old, which is why it pays to look at both while the plumber is there.

It also helps to know who is responsible. Under NSW strata rules, the owners corporation looks after common property, and pipes that serve more than one lot are generally common property. A shared drain running along the side of a block is usually the owners corporation's to maintain, so the repair goes through the strata manager rather than one owner.

Signs tree roots are blocking your drain

• Drains that gurgle or run slowly, then clear, then slow again. Roots build up gradually, so the blockage comes and goes before it becomes total.
• A blockage that returns within months of being cleared. The roots were pushed aside, not removed.
• Water sitting in a drain opening or gully outside, especially in a side passage or courtyard that nobody checks often.
• More than one apartment noticing slow drains at the same time, which points to the shared line rather than one unit's plumbing.
• Large trees within a few metres of the drain line, including street trees near the front boundary.

If any of these sound familiar, get the drain looked at before it backs up. Roots are far easier to deal with while the drain is still flowing than after it overflows into a courtyard or a ground-floor unit.

Contact Norton Plumbing

Norton Plumbing has cleared blocked drains and worked on strata buildings across the Eastern Suburbs since 2019, from Paddington through to Coogee, Bondi, Randwick and Maroubra. Adam Norton is the primary plumber on the tools and holds NSW plumbing licence 397768C. Phone 0477 858 951. Based at 10/11a-15 Berwick Street, Coogee NSW 2034. See our blocked drains service page, our strata plumbing page, or our Paddington plumber page.