Tree roots get into sewer pipes through cracks and loose joints, especially in older clay (terracotta) pipes. Once inside, they grow, trap waste and cause repeat blockages or a broken sewer pipe. Cutting the roots out gives short-term relief. Relining or replacing the damaged section seals the entry points so the roots can’t come back.
If your home was built decades ago, there’s a good chance the sewer pipe running under your yard is clay. Those pipes were laid in short sections joined together. Over the years, the joints loosen, the ground shifts and small cracks open up.
That’s all a tree root needs.
Tree roots in sewer pipes are one of the most common causes of a broken sewer pipe and repeat blockages in Sydney’s older suburbs. This guide explains why it happens, the signs to look for and how a sewer renewal stops it for good.
Sewer backing up or gully overflowing? Call Jetstar Plumbing on 02 9073 4415. 24/7, free call-out fee.
Why Tree Roots Get Into Sewer Pipes
Sewer pipes carry water and nutrients, and they give off moisture and warmth into the soil around them. Roots grow towards that.
How roots get in
- Through loose or cracked joints. Clay pipes were joined in short lengths. Each joint is a possible gap.
- Through cracks in the pipe wall. Ground movement, age and nearby digging can crack pipes.
- At the junction. The point where your pipe connects to the sewer main is another weak spot.
Sydney Water’s diagram of incorrect private plumbing connections shows roots getting into pipes through cracks and joints. Those cracks also let groundwater into the pipe.
What happens next
Fine roots enter the gap and keep growing inside the pipe. They form a net that catches toilet paper, wipes and grease. As the root mass grows, it can widen the crack, push joints apart and eventually break the pipe.
Why Older Sydney Homes Are Most at Risk
Many older homes across Sydney’s established suburbs were built with clay sewer lines. Add mature trees in front yards and on nature strips, and root problems are common.
Clay pipe itself can last a long time. The weak points are the joints and any cracks. Modern PVC pipes have far fewer joints, and those joints are sealed more tightly. That’s why some councils, such as Waverley Council, suggest owners with repeat blockages consider upgrading private sewer lines to PVC.
Signs of Tree Roots in Your Sewer Pipe
- Slow drains throughout the house, not just one sink
- Gurgling toilets or basins
- The outdoor gully trap overflowing or bubbling
- Blockages that come back every few months
- Sewage smells in the yard
- Lush, extra-green patches of lawn along the pipe line
- Sunken ground or small sinkholes near the pipe
If a plumber has already pulled roots out of your drain once, it’s very likely they’ll be back.
Root Cutting vs Sewer Renewal
| Root cutting / hydro-jetting | Pipe relining | Dig-and-replace | |
| What it does | Cuts roots out and clears the pipe | Seals the pipe from inside | Removes damaged pipe, lays new PVC |
| Stops roots coming back? | No, roots regrow through the same gap | Yes, cracks and joints are sealed | Yes, the old pipe is gone |
| Digging | None | Little to none | Yes |
| Best for | Emergency relief, or before relining | Root-damaged pipe that holds its shape | Collapsed or badly broken pipe |
| Long-term fix? | No | Yes | Yes |
Cutting roots is often the first step in an emergency. But as a long-term plan, regular cutting means paying again and again while the pipe keeps getting worse.
For a full cost comparison, see our guide to sewer pipe relining vs dig-and-replace.
Who’s Responsible When Roots Block Your Sewer?
According to Sydney Water, property owners are responsible for their connection to the wastewater system (the point of connection). That includes clearing tree roots that enter the junction, and any damage to the junction caused by tree roots.
So even when the problem is near the boundary, it’s often the homeowner’s job to fix. A CCTV drain inspection shows exactly where the roots are.
If sewage is overflowing from a maintenance hole on the street or footpath, that’s Sydney Water’s network. Report it on 13 20 90.
What Affects the Cost of Fixing Root-Damaged Pipes
| Factor | Why it matters |
| How far the roots have spread | More affected pipe means more relining or digging |
| Pipe condition | Cracked pipe can be relined; collapsed pipe needs replacing |
| Pipe length and diameter | Larger and longer pipes cost more to renew |
| Access | Easy access through an inspection opening keeps costs down |
| What’s above the pipe | Driveways, paths and gardens affect digging and restoration costs |
| Number of junctions | Each branch line needs extra work during relining |
We price the job after a CCTV inspection, so you know the cost before any work starts.
As a 2026 estimate, most residential pipe relining jobs in Sydney fall between about $3,000 and $15,000. See the full price breakdown in our guide to sewer pipe relining vs dig-and-replace.
The Jetstar Plumbing Process – Step by Step
- Call or book online. Ring 02 9073 4415 or book online. Free call-out fee.
- Clear the roots. We cut and flush the roots to get your sewer flowing again.
- CCTV drain inspection. We find where the roots are getting in and check the pipe’s condition.
- Show you the footage. You see the cracks, joints and roots for yourself.
- Recommend the fix. Relining, replacement or a mix, based on the camera.
- Renew the pipe. Our licensed team seals or replaces the damaged sections.
- Final camera check. We confirm the pipe is clear and sealed.
Common Mistakes With Tree Roots and Sewer Pipes
- Relying on regular root cutting for years. Each cut buys time while the cracks get bigger.
- Pouring root killers or harsh chemicals down the drain without advice. Speak to a licensed plumber first.
- Planting large trees near the sewer line. Check where your pipes run before planting.
- Removing a tree and assuming the problem is gone. Dead roots can still block a pipe, and the cracks they made remain.
- Ignoring early signs. A root problem caught early is more likely to suit relining rather than digging.
- Using an unlicensed operator. Drainage work in NSW needs a licensed plumber or drainer. Check a licence on NSW Fair Trading.
Roots are also a common cause of sewer overflows. Read what causes sewer overflows in Sydney homes, or see our blocked drains service.
Why Sydney Homeowners and Agents Call Jetstar Plumbing
- 20+ years serving homes and businesses across Sydney
- Fully licensed, bonded and insured (Licence 166837C)
- 24/7 emergency plumbing, 7 days a week
- Free call-out fee and a 100% satisfaction guarantee
- Trusted by leading real estate agencies, including Belle Property, LJ Hooker and Stone, through our property maintenance program
For landlords and property managers, sorting root damage properly means fewer repeat callouts and fewer unhappy tenants.
Frequently Asked Questions
How do tree roots get into sewer pipes?
Roots grow into small cracks and loose joints, drawn by the water and nutrients inside. Older clay pipes, with many joints, are most at risk.
How do I know if I have tree roots in my sewer pipe?
Slow drains, gurgling toilets, an overflowing gully and repeat blockages are common signs. A CCTV drain inspection confirms it and shows where the roots are.
Will cutting the roots fix the problem?
Only for a while. Cutting clears the pipe, but roots regrow through the same cracks. Relining or replacing the pipe is the long-term fix.
Can a pipe with tree roots be relined?
Yes, if the pipe still holds its shape. The roots are cleared first, then the liner seals the cracks and joints. If the pipe has collapsed, that section usually needs replacing.
Who pays to remove tree roots from the sewer junction?
Sydney Water states that property owners are responsible for clearing tree roots that enter the junction at the point of connection.
Should I remove the tree?
Not always. Fixing the pipe stops the roots getting in. Talk to an arborist before removing a tree, and check any council tree rules.
Are PVC pipes better than clay pipes for roots?
PVC pipes have fewer joints and tighter seals, so roots have fewer ways in. That’s why upgrading or relining old clay lines is common.
Stop Tree Roots Breaking Your Sewer
If roots keep blocking your drains, the pipe needs fixing, not just clearing. Jetstar Plumbing will clear the line, show you exactly what’s happening and recommend the right renewal.
Call 02 9073 4415 or book online. 24/7 emergency plumbing, free call-out fee, Sydney-wide.
