The short answer
Signs of roots in a sewer line are several drains slowing down at once, toilets gurgling, a sewage smell outside, the overflow relief gully filling up, and blockages that come back after being cleared. Water Corporation says a hairline fracture is all a root needs to get in, and that homes over 15 years old are more at risk because they’re less likely to have PVC sewer pipes. Blockages in the property plumbing are the owner’s responsibility; blockages in the sewer main, normally outside the property, are Water Corporation’s. If wastewater is overflowing, call Water Corporation on 13 13 75. To clear a root blockage on your side, call McDermott Plumbing on (08) 6187 3999 or text 0406 882 648.
Signs roots are in the line
- Several fixtures draining slowly at the same time, not just one sink.
- Toilets gurgling or bubbling when the shower or washing machine empties.
- The overflow relief gully outside filling with water, or wet ground around it.
- A blockage that was cleared and came back weeks or months later.
- A sewage smell in the yard, or one strip of lawn that stays greener than the rest over the line.
Why older pipes get roots and newer ones mostly don’t
Water Corporation’s tree guidance for Perth puts it plainly: roots go looking for moisture, a property’s sewer pipes are an attractive source, and a small hairline fracture is all a root needs. Once inside, the root grows quickly, slows the flow and can block the pipe completely. Often whole sections of pipe then need replacing. It also says homes over 15 years old are particularly at risk because they’re less likely to have PVC sewer pipes, which aren’t as prone to leaks and root damage.
That matches what we see. Established suburbs with older clay or earthenware sewer lines and decades-old street and garden trees get root chokes far more often than newer estates laid in PVC. PVC isn’t immune, though. A joint that has moved, a pipe cracked during landscaping, or a big tree planted right on the line can still let roots in.
Who pays: you, Water Corporation, or whoever owns the tree?
Water Corporation’s rule is that blockages within the property plumbing are the owner’s responsibility, and blockages in the sewer main, normally outside the property, are theirs. Its building and plumbing handbook says owners pay for clearing any blockage in the property sewer connection (the pipe between the inspection shaft and the junction on the main) where it can be cleared from the inspection shaft. If a repair to that connection needs a dig of 2.5 metres or more, or a dig outside the property, Water Corporation will assist the plumber with the excavation.
If we find the blockage is in the main, we call Water Corporation, their crew clears it, and Water Corporation pays the plumber a standard fee for locating it.
Whose tree it is doesn’t change who looks after the pipe. If the roots come from a neighbour’s tree or a verge tree, that’s a separate conversation with the neighbour or the council. The blocked line on your side still needs clearing first. In a rental, the tenant should report it to the landlord or agent, and the landlord or agent books the plumber.
Insurance
Policies vary a lot. Some home insurance covers sudden water or sewage damage from a blocked or broken pipe but not the gradual damage roots do to the pipe itself. Check your policy wording, take photos before anything is cleaned up, and keep the plumber’s invoice that describes the cause.
What we do about roots
We clear the blockage from the most sensible access point, usually the inspection shaft or a gully, with a drain machine, and check that the line runs freely again. Then we tell you what we found: a one-off choke, or a pipe that roots will keep getting back into.
Clearing roots treats the symptom. They usually grow back into the same crack. If it keeps happening, we’ll talk through the options, including inspecting the line and repairing or replacing the damaged section, and we’ll be straight about what we do ourselves and what needs a specialist.
What not to do
- Don’t tip strong drain chemicals into a blocked sewer. They sit in the pipe, can burn you if the line backs up, and rarely shift a root mass.
- Don’t keep flushing to push it through. Every flush adds to what may come up through the gully or a floor waste.
- Don’t plant large trees right over the sewer line. Water Corporation’s Perth-Peel tree list scores species for how invasive their roots are, which is worth a look before you plant.
Common questions
- How do I know if tree roots are in my sewer pipe?
- Several drains slowing at once, gurgling toilets, an overflow relief gully that fills up, and blockages that keep coming back are the usual signs. A plumber can confirm it when clearing the line.
- Who is responsible for tree roots in a sewer pipe in Perth?
- Blockages in the property plumbing, up to the junction with Water Corporation’s main, are the owner’s responsibility. If the blockage is in the main, Water Corporation clears it. Whose tree it is doesn’t change who looks after the pipe.
- Will the roots come back after the drain is cleared?
- Often, yes. Clearing removes the roots inside the pipe but not the crack or joint they came through. If a line keeps blocking, it’s worth talking about repairing that section rather than clearing it again and again.
- Does home insurance cover tree root damage?
- It depends on the policy. Some cover sudden damage from a blocked or broken pipe but not the gradual damage roots do to the pipe. Check your wording and keep photos and the plumber’s invoice.
- Do you do pipe relining?
- We don’t advertise pipe relining. We clear root-blocked property sewers and tell you what we found and what your options are. If the fix needs something we don’t do, we’ll say so.
Related pages
Official sources
Last updated 6 October 2026. General information only. Every property is different, so call us to talk about yours.