11 Aug 2020

Tree roots vs drain pipes: How to be on the winning team

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In Melbourne we love our treelined suburban streets – they provide shade, filter the air, and look beautiful. But underground, your favourite tree could be causing serious and expensive damage to your stormwater or sewer pipes. Here we walk through why tree roots cause blocked drains and how to fix the problem.

How tree roots block drains

Tree roots will grow wherever they can, regardless of where your pipes are. They are drawn to the condensation on the outside of sewer or stormwater drains, which forms near tiny cracks, spaces between joins or imperfections in your pipe. They are powerful enough to grow through the crack to the source of more water, where they can grow and grow. As more water comes down your pipes, the bigger the tree roots will grow. The roots form a type of net, and waste that goes down your pipes can’t pass through, causing a blockage.

A blockage shows up in the form of overflowing pipes, slow draining baths or sinks, gurgling noises or bad smells.

Clay pipes are the most susceptible to having tree roots issues, and they are older and are installed in smaller sections. The sections are joined with cement, which deteriorates over time. All of this contributes to weak points for roots to penetrate.


How to fix the problem

When you call a plumber for a blocked drain, they bring special machinery to inspect, locate and clear blocked drains. This includes a machine that has a large cable with a cutting head, cutting back the roots and clearing the blockages.

We also recommend using the CCTV camera (a long cable with a camera on the head) which is sent down the pipe to see the extent of the damage to the pipe and locate exactly where the tree roots are coming in.  This CCTV camera emits a sonar signal, and with our specialised equipment, we can track where the camera is, even if it’s under concrete 3 metres deep!  This then enables us to work out exactly where the issue is and accurately quote the repair.

If you’ve had tree roots in your pipes once, there is a high chance you will have them over and over again – the roots will keep finding the same imperfection, space between joins or crack in the pipe and keep growing through it. Some companies suggest relining, however this is a temporary fix – it is like treating the symptoms rather than the cause.

The only way to ensure tree roots do not grow back into your pipes (and cause future blockages) is by replacing the section of pipe the roots have come through with long lasting UPVC pipes.  You can also ask your plumber to install an inspection point at the trouble spot, for easier access in clearing future problems.


What not to do

Plumbers do not recommend the following to clear drain roots:

  • Putting any sort of poison, herbicide or weed killers down your drains to kill the roots. This is not only ineffective, but also illegal (as monitored by EPA Victoria). These poisons go down your pipes and into our waterways, which is harmful to the environment and public health.
  • Putting rocksalt down the pipes to dry up the roots – once again, likely ineffective and not recommended. You should not put anything down your pipes other than standard waste.
  • Putting boiling water down your pipes – this one is just a waste of water! The heat loss from the time the water travels from your sink to the tree outside renders this ‘solution’ completely ineffective.



You can purchase a copy of your property sewerage plan from your water retailer (such as Yarra Valley Water or South East Water) before planting any new trees. This will help you plan that your landscaping is not impacting your existing plumbing.   Try to plant trees at least 5 metres away from your property’s sewer or stormwater pipes. and ensure they are pruned and watered regularly so they don’t need to send out roots in search of water.

If you are creating a new building, take into account where existing trees are (including your neighbour’s trees) and don’t lay any pipe near them.


Call the Experts

Sometimes it takes more than a clever landscaping to fix a blocked drain. In cases like these, you can’t go past the services of Expert Plumbing & Gas Services. You can reach us by calling 03 9486 5907 or filling out a contact form today!