Tree Root Drain Intrusion: Relining vs Root Cutting vs Tree Removal

Tree roots in drain pipes are one of the most common, and most misunderstood, plumbing problems on the Central Coast. Many homeowners get their drains jetted and roots cleared, assume the problem is fixed, and then face the same blockage 12-18 months later. The reason: clearing roots from inside a pipe doesn’t fix the entry point. This guide explains your options, which ones actually work long-term, and what they cost.

The short answer

Root cutting (jetting or electric eel) clears roots temporarily. Drain relining permanently seals the entry points, joints and cracks, that roots exploit. Unless you also remove the tree (which often isn’t practical or legal), relining is the only long-term solution that stops roots coming back. Tree removal alone doesn’t help unless the pipe entry points are also sealed.

How tree roots get into drain pipes

Tree roots don’t break into pipes, they find existing openings. The two main entry points are:

1. Deteriorated mortar joints: In clay and terracotta pipes, the mortar between sections dries and crumbles over decades. Gaps form. Root tips as thin as a hair can enter these gaps and then grow inside the pipe.
2. Cracks: Any crack in a pipe body allows root entry. Cracks form from ground movement, vehicle loading, hydrostatic pressure and simple age.

Once inside, roots grow rapidly because:

• The temperature inside sewer pipes is stable and warm
• Nutrients (from sewage) are plentiful
• Moisture is continuous

Root growth inside a pipe starts as a fine fibrous mat and eventually becomes a dense mass that catches toilet paper and solids, creating a full blockage.

The four options: comparison

The most common mistake is using temporary solutions repeatedly without addressing the pipe entry point. Roots cleared in 2020 will typically regrow to a blocking level by 2021-2022. Repeated jetting adds up, three jetting visits over three years might cost $1,200, $1,500, while relining once for $5,000 solves the problem for 50+ years.

Why root cutting is not a long-term solution

Electric eel (also called a drain snake or drain auger) is a mechanical cable that cuts roots physically. It’s effective at clearing a blockage immediately. So is hydro jetting (high-pressure water). But both methods:

• Don’t change the pipe condition
• Don’t seal the joints that roots entered through
• Don’t prevent roots from regrowing from the cut point
• Often leave root stubs inside the pipe that regrow faster than the original growth

You’ll need this done again. And again. It’s maintenance, not repair.

Chemical root killers: worth using?

Copper sulphate crystals flushed down the toilet are a decades-old folk remedy for root intrusion. They have limited effectiveness because:

• The chemical needs to contact the roots, but sewage flow dilutes it rapidly
• Copper sulphate is toxic to roots only at concentrations that are difficult to achieve in a flowing sewer
• It may slow regrowth slightly but doesn’t seal joints
• Foaming root killers are more effective at coating the pipe interior but are still temporary

Some arborists also note that copper sulphate can damage the tree’s root system more broadly, creating tree health problems you didn’t want. For trees in good condition on Central Coast properties, this is rarely a desirable approach.

Why tree removal alone doesn’t fully solve the problem

If you cut down the tree, new root growth stops. But:

• The roots already inside the pipe don’t disappear, they decay over months to years and cause intermittent blockage as decaying material breaks off
• The joints and cracks that allowed root entry remain open and can eventually allow soil infiltration or groundwater entry
• Adjacent tree root systems from neighbouring properties can find the same entry points

Tree removal is a valid choice if the tree was causing other problems, but it should always be combined with drain relining or at minimum a CCTV inspection to assess whether the entry points need to be sealed.

What drain relining does differently

Drain relining doesn’t cut or poison the roots, it seals the entry points permanently. Here’s the sequence:

1. Hydro jet clears the current root mass from inside the pipe
2. CCTV inspection confirms the pipe bore is clear and maps all defects (entry points)
3. Liner installation, the resin liner is installed inside the cleaned pipe, covering every joint and crack
4. After cure, the liner is a smooth, jointless new pipe inside the old one. There are no openings for roots to enter

The roots from the tree outside remain alive. They’ll continue seeking moisture. But there’s nothing to enter. They divert around the pipe and grow elsewhere.

Which trees are the worst offenders on the Central Coast?

Coastal properties near Avoca Beach, Terrigal and Umina with large established trees warrant a CCTV inspection regardless of symptoms, it’s better to know what’s coming.

How to decide: reline now or monitor?

If your CCTV shows:

• Dense root mass, multiple entry points across the pipe run: Reline now. The pipe is compromised throughout.
• Roots at 2-3 joints, pipe body intact elsewhere: Full relining makes sense. Point repairs at just the affected joints are an option but less reliable.
• Minor root wisps at one joint, pipe otherwise good: Monitor with annual CCTV + jetting. Consider relining in 2-3 years if growth accelerates.
• Any structural collapse or severe cracking alongside root intrusion: Reline as priority, the structural issue won’t wait.

Cost of root-related drain work on the Central Coast

Frequently asked questions

Will the tree die if I reline the pipe and it can’t access the moisture inside? No. Trees don’t depend on sewer pipes for water, they were getting water from the soil and rainfall long before they found the pipe. The moisture from the sewer is a bonus source. Cutting off that source simply redirects the roots. The tree’s health is not affected by drain relining.

Can I reline a pipe that’s completely blocked with roots? Not directly. The pipe must be cleared of roots first (hydro jetting) before the liner can be installed. If the pipe is so severely root-invaded that it can’t be jetted clear, an excavation at that point may be required first.

How soon after a root blockage clear should I get relining? Ideally within weeks. After jetting, root stubs remain and regrowth begins immediately. The longer you wait, the more regrowth there will be. Most relining contractors will do the CCTV and liner in the same visit or within a few days.

Will Council make me remove my tree if it’s causing drain problems? Council has no authority to direct you to remove a tree specifically for drain purposes. However, if your pipe is exfiltrating sewage (leaking), Council can require you to repair the pipe. The repair (relining) doesn’t require tree removal.

Does the Central Coast have particular root intrusion problems compared to other areas? Yes. The coastal climate, established garden culture and prevalence of older AC cement and terracotta pipes make root intrusion one of the most common drain issues across Gosford, Wyong, Terrigal and Erina.

Have root-invaded drains? Book a CCTV inspection or get a relining quote.