Tree Roots in Pipes: Signs, Fixes and Who Pays in Adelaide

Tree roots in pipes are one of the most common causes of a blocked sewer in Adelaide, especially in established suburbs with mature street trees and older clay drains. Roots are drawn to the moisture and nutrients inside sewer lines. Once a fine root finds a hairline crack or loose joint, it grows inside the pipe, catches toilet paper and waste, and slowly chokes the drain until something backs up.

This guide covers how roots get in, the signs of a blocked drain to watch for, how a plumber finds and fixes the problem, and who is responsible under SA Water’s rules. If your drain is already backing up, our blocked drains page explains how to send an enquiry.

How do tree roots get into pipes?

Roots enter through weak points, not solid pipe. In many older Adelaide homes, the sewer drain is made of short lengths of glazed clay pipe joined with rubber rings or mortar. Over decades those joints loosen and the pipe can crack.

Adelaide conditions make this worse:

• Reactive clay soils. Much of Adelaide sits on clay that swells in wet winters and shrinks in dry summers. That movement can shift pipe joints and open gaps.
• Mature trees. Gums, figs, jacarandas, plane trees and many shrubs send roots a long way in search of water, particularly during long dry spells.
• Older drains. Clay pipes in post-war and earlier homes have had decades to settle and crack.

Once inside, roots grow quickly because the pipe gives them a steady supply of water and nutrients. A small root mass can become a thick mat that fills the pipe.

What are the signs of a blocked drain caused by roots?

SA Water lists the common signs of a blocked drain, and root blockages show them in a typical pattern. Use this checklist:

• Slow drainage in sinks, showers, baths or toilets.
• Gurgling noises from toilets or floor wastes when water drains elsewhere.
• Overflowing water at the outdoor overflow gully, or a toilet that rises before it drains.
• Several fixtures affected at once, which points to a blockage in the main drain rather than one sink.
• The problem keeps coming back after being cleared, often worse after rain or in dry seasons.
• Sewage smells outside near the drain line, or soggy patches in the lawn.
• Lush green grass in a strip across the yard, which can mean a leaking sewer line.

A single slow sink is more likely to be a local blockage from food, hair or grease. Read the best way to unblock a drain for safe first steps with a single fixture. When several fixtures are affected, think main drain and think roots.

Who is responsible for tree roots in the drain?

SA Water says the location of the blockage determines who needs to fix it.

Where the blockage is	Who fixes it	What to do
In your private pipes on your property	The property owner	Contact a licensed plumber to investigate.
In the public sewer system	SA Water	Report it on SA Water’s faults line, 1300 729 283, or through its faults and outages map.
Not sure	Start by asking	SA Water will ask questions to work out the likely location and cause.

Your plumber can usually tell from a camera inspection which side the blockage is on. Tenants should report drain problems to their landlord or property manager.

How does a plumber find and clear tree roots?

Most plumbers follow a three-step approach: find it, clear it, fix it.

1. Camera inspection. A small waterproof camera on a cable is pushed through the drain, usually from the overflow gully or an inspection opening. It shows where the roots are, how much pipe is affected and whether the pipe is cracked, collapsed or sagging.
2. Clearing. A high-pressure water jetter or a mechanical cutter clears the roots and restores flow. This gets the drain working again, often on the first visit.
3. Repair options. Because roots grow back through the same gaps, the plumber will discuss a longer-term fix.

Repair option	How it works	When it suits
Regular clearing	Jetting the line again when roots return	Short term, or when a bigger repair isn’t possible yet.
Pipe relining	A resin liner is cured inside the old pipe, sealing cracks and joints	Pipe still mostly in shape, digging is hard (driveways, paving, gardens).
Section replacement	Digging up and replacing the damaged length with modern pipe	Collapsed or badly sagging pipe, or where relining isn’t suitable.
Tree management	Removing or managing the problem tree	Repeated damage from one tree close to the line.

How can you prevent tree roots getting into pipes?

You can’t make clay pipes root-proof, but you can reduce the risk:

• Think about where pipes run before planting. SA Water advises avoiding planting trees near pipes and publishes a tree planting guide.
• Have older clay lines checked with a camera before a renovation, a sale, or if you notice early signs.
• Only flush the three Ps (pee, poo and toilet paper). Wipes and sanitary items snag on roots.
• Use sink strainers so food and fat don’t build up on root masses.
• Don’t run the washing machine or dishwasher while drains are slow, as SA Water also recommends.

If a large tree is the cause, an arborist can advise on whether it can be managed or needs to come out. Our sister site Tree Fox covers tree work.

What about homes on septic tanks or CWMS?

Not every Adelaide property drains to the main SA Water sewer. Many homes in the Adelaide Hills and some outer suburbs are on a septic tank or a council-run Community Wastewater Management System (CWMS). Roots cause the same kind of trouble in these systems: they get into the drain between the house and the tank, into the tank itself, or into soakage trenches.

The difference is who looks after which part. On a CWMS, the council or scheme operator usually looks after the scheme’s pipes, while the property owner looks after the drains from the house to the connection point. With a private septic system, the owner is generally responsible for the whole system on their land. Check with your council if you are unsure which applies to you.

Tell the plumber up front if you are on septic or CWMS, because the camera access point, the clearing method and any repair can differ. Our Adelaide Hills page covers more about local plumbing conditions.

Can you clear tree roots yourself?

You can do some safe checks, but not much more. Plungers and hardware-store augers rarely shift a root mass in the main drain, and pushing hard on an old clay pipe can make a crack worse. Chemical drain cleaners can damage pipes and make the job unsafe for the plumber if they sit in a blocked line.

Safe steps while you wait:

• Stop using water in the house as much as you can.
• Check the outdoor overflow gully. If it is overflowing, keep children and pets away.
• Don’t lift sealed inspection caps if the line is under pressure.
• Take photos of any overflow for your records.

When should you call a licensed tradie?

Call a plumber when:

• Several fixtures are slow or gurgling at the same time.
• Sewage is coming up through the gully, a floor waste or a shower.
• The same drain has been cleared before and is blocking again.
• You can smell sewage in the yard.
• You are buying an older home and want the sewer line checked.

If you believe the blockage is in the public sewer, report it to SA Water on 1300 729 283. For other plumbing help, see our Adelaide plumber page or the emergency plumber service for urgent overflows.

Getting it sorted

Send one enquiry through our contact page or call 08 6800 6079. We pass it to one local plumber, who calls you back within 24–48 hours to discuss the drain and quote before any work starts. For overflowing sewage, choose Urgent on the form; we can’t promise an arrival time.