Tree roots in drains is the single most common cause of recurring Melbourne blockages. It is also the most expensive to fix properly. Here is what is actually happening and what your options are.
How roots get into drains
Sewer drains carry a constant supply of moisture and nutrients. To a tree, this is a buffet. Roots seek out any tiny crack or imperfect joint in your sewer pipe. Once a root finds an opening, it grows inside the pipe. Over years, the root mass builds until water can barely get through.
The worst Melbourne offenders
Liquidambar (the autumn-leaf tree) is probably the biggest offender. Big trees, aggressive roots, common in inner Melbourne. Camphor laurel, plane trees (London plane is everywhere in Melbourne), fig species, and most large eucalypts. If any of these are within 10 metres of your sewer line, you are at risk.
Why DIY does not work long-term
You can pour chemical root killers down the toilet. They kill the roots that are in the pipe at that moment. They do not stop new roots growing in through the same opening within months. Same with hand-clearing.
What actually works: jetting
High-pressure water jetting cuts through root masses without damaging the pipe. A good jet clear lasts 6 to 18 months before the same roots regrow. For modest root problems, this is the cheapest practical option. Cost in Melbourne is around $400 to $700 per session.
Better fix: pipe relining
Relining inserts a resin-impregnated sleeve into the existing pipe. The sleeve hardens into a smooth new pipe within the old one. Roots cannot grow through the new lining. No digging required - the work is done through the existing inspection point.
Cost is typically $300 to $500 per linear metre. For a 5 metre section of root-affected pipe, that is $1,500 to $2,500. Sounds expensive until you compare to clearing it every 12 months for the next 20 years.
Worst case: pipe replacement
If the pipe is too damaged for relining (collapsed sections, multiple severe breaks), you have to excavate and replace. Cost varies hugely with depth and access but $5,000 to $15,000 is realistic for a typical residential job.
What we recommend
Get a CCTV inspection if you have recurring blockages. The video tells you the severity and the best fix. For mild root problems, a yearly maintenance jet might be cheapest. For moderate to severe problems, relining usually pays for itself within 3 to 5 years.