Tree roots are the single most common cause of serious drain blockages we attend across Perth, and it is not close. Sand country gardens rely on deep rooted trees for shade, those trees spend summer hunting for moisture, and the most reliable water source on many blocks runs conveniently underground in a straight line toward the street. Once roots find a sewer, they do not leave voluntarily. Prevention is therefore a far better investment than removal, and after decades of cutting roots out of Perth pipes we can tell you exactly what prevention looks like.
Understand how roots actually get in
Roots do not crush their way into sound pipes. They follow moisture vapour escaping from tiny imperfections, a hairline crack, a slightly displaced joint, a degraded rubber seal, and send fine feeder roots through the opening. Inside the pipe they find water, oxygen and nutrients in abundance, and the fine roots thicken into a mass that catches paper and waste until the line closes over. This matters because it tells you where the risk truly sits. A structurally sound modern PVC line with welded joints gives roots almost nothing to work with. The older clay and concrete pipes under much of established Perth, laid in short sections with joints every metre or so, offer an entry point at every join.
Know your enemy in the garden
Some species are dramatically worse than others. Ficus and rubber trees are notorious, and we would not plant one within cooee of a sewer line. Willows, poplars, liquidambars and large eucalypts follow close behind. As a working rule, fast growing trees with aggressive surface roots and high water demand are the ones that find pipes. If you are planning new planting, keep large trees well clear of the sewer alignment, and favour smaller, slower species with contained root systems anywhere near pipework. Your local nursery can point you to root friendly options that still deliver shade.
Find out where your pipes actually run
Most homeowners have only a vague idea where their sewer runs, and plant trees directly over it in blissful ignorance. Water Corporation can provide the location of mains and connection points, and the layout of your private drainage is typically documented on the drainage plan lodged when the house was built. Ten minutes with that plan changes your planting decisions permanently. If no plan exists, our locators can trace the line precisely, which is also the first step before any pool, shed or extension goes in.
The maintenance habits that keep roots out
Water and feed trees deeply but less often, which trains roots downward rather than encouraging shallow lateral hunting. Fix leaking taps, dripping air conditioner condensate lines and weeping retic fittings promptly, because a constant damp patch near the sewer alignment is an engraved invitation. And watch for the early warnings, a toilet that gurgles, a drain that slows each summer, a patch of lawn that stays suspiciously green through February. Roots announce themselves quietly before they block anything, and acting on the whisper costs a fraction of acting on the flood.
Inspection is the prevention nobody skips twice
A CCTV camera inspection shows the inside of your sewer in real time, and it converts guesswork into fact. It reveals whether roots have entered, where, and how badly, and it shows the joint displacement or cracking that will admit them next. For properties with established trees anywhere near the line, we recommend a camera inspection every couple of years. Every client who has been through one root blockage books the follow up inspection without being asked. It is the cheapest insurance in drainage.
When roots are already in
If roots are established, high pressure water jetting with a root cutting head clears the line thoroughly, and far more effectively than mechanical snaking, which tends to punch a hole through the mass and leave the walls furred with regrowth points. But clearing is treatment, not cure. The entry point remains, and roots regrow toward a known water source faster than they found it the first time. The permanent fix is sealing the entry, which today rarely means excavation. Pipe relining installs a new seamless liner inside the existing pipe, bonding across the cracks and joints so there is nothing left for a root to follow. One reline typically ends a root problem that jetting alone would need to revisit year after year.
The Perth reality
In older suburbs with clay pipes and mature gardens, some root intrusion is close to inevitable over a long enough timeline. The difference between an inconvenience and a disaster is entirely about timing, and timing is something you control. Know where your lines run, plant with intent, watch for the early signs and put a camera through the line before summer rather than after the blockage. If you suspect roots have already found their way in, call Drains Plus. We have been evicting them from Perth sewers for more than 25 years, and we know every trick they have.
One last prevention option worth knowing about is foaming root treatment, a herbicide foam applied inside the line that kills the fine roots at the pipe wall without harming the tree above. It has a legitimate place as a holding measure between clearances or ahead of a planned reline, particularly where a valued mature tree sits over an old line and nobody wants to lose it. What it is not is a permanent fix, since it treats the roots rather than the opening they came through, and it needs reapplying as regrowth returns. We are always happy to explain where treatment fits and where it is money better put toward sealing the pipe.
