Understanding why pipes burst helps you prevent expensive emergencies. Here are the seven most common causes and what you can do about each one.
Steel pipes typically last only 20 to 50 years, even when galvanised. If you are living in an older property and experience a burst pipe, it may simply be that your steel pipes have reached the end of their serviceable life.
Galvanisation (zinc coating) protects steel from corrosion, but this protection degrades over decades of use. Once the zinc layer wears through, the underlying steel corrodes rapidly from the inside out.
Prevention: If your property has original steel pipes older than 30 years, consider proactive replacement with modern PVC or copper before they fail. PVC has a significantly longer lifespan and is not susceptible to corrosion.
PVC pipes, while having a longer lifespan than steel, can be physically damaged by building work or excavation. If you discover a burst pipe and notice that neighbours have recently started renovating or excavating near your property boundary, it is worth investigating whether vibration or direct contact caused the damage.
Even work on your own property — landscaping, fence installation, or driveway construction — can inadvertently damage underground pipes if their location is not identified beforehand.
Prevention: Before any excavation work, call Dial Before You Dig (1100) to locate underground services. If construction is occurring nearby and you notice changes in water pressure or unexpected wet patches, have your pipes inspected promptly.
Metal pipes are prone to rust, which gradually weakens the pipe wall from the inside. Changing water pressure accelerates this deterioration, creating thin spots that eventually give way.
Warning signs:
If you notice these symptoms, your pipes are corroding internally and a burst is likely if not addressed. A plumber can assess the extent of corrosion and recommend targeted replacement of the worst sections.
Areas with hard water experience gradual calcium and magnesium deposits inside pipes. Over time, these mineral deposits narrow the pipe diameter, increase internal pressure, and create weak points where bursts can occur.
While you cannot control your local water quality, regular maintenance and periodic descaling can help manage the build-up. Properties in hard water areas should be inspected more frequently for signs of restriction.
Prevention: Consider a water softener system if your area has particularly hard water. Schedule regular plumbing inspections to monitor pipe condition and catch narrowing before it causes a failure.
Tree roots are an ongoing cause of pipe damage, particularly in sewer lines and stormwater drainage. Large trees send root systems deep underground searching for moisture, and even small cracks or joints in pipes provide an entry point.
Once inside, roots expand and exert enormous pressure on pipe walls, eventually cracking or crushing them. This is especially common with older terracotta and concrete pipes that have more joints and are more brittle.
Prevention: Before planting trees, check that their root systems are not aggressive and that they are positioned well away from underground pipes (minimum 3 metres). If you have existing large trees near your sewer or water lines, schedule annual CCTV drain inspections to catch root intrusion early.
Long periods of either wet or dry weather cause changes to the soil around your property, making pipes shift and move. Clay soils are particularly problematic — they expand when wet and contract when dry, creating ground movement that stresses pipe joints.
In NSW, the cycle between drought and heavy rain means pipes are constantly subjected to soil movement. This stress accumulates over years, eventually causing joints to separate or pipe walls to crack.
Prevention: Maintain consistent moisture levels around your property where possible. Ensure drainage directs water away from foundations and pipe routes. If you notice ground movement or cracking in walls or paths, have your underground pipes inspected.
Sometimes burst pipes are the result of substandard work done years earlier — by a previous owner attempting DIY, or by an unqualified tradesperson taking shortcuts.
Common issues include:
Prevention: Always use a licensed plumber for any pipe work. Check that they provide a compliance certificate for the work performed. If you have purchased a property and are unsure of its plumbing history, a full plumbing inspection can identify potential weak points before they fail.
Steel pipes typically last 20–50 years, copper 50–70 years, and PVC 50–100+ years. Age, water quality, soil conditions and maintenance all affect lifespan.
Yes. Tree roots exert enormous pressure as they grow. They can crack, crush or completely collapse pipes — particularly older terracotta and concrete sewer lines.
Warning signs include discoloured water (yellow/brown), metallic taste, reduced flow from taps, and rust stains on fixtures. A plumber can perform a CCTV inspection to assess internal condition.
Shut off the main water supply immediately, move valuables away from the affected area, document damage with photos, and call a licensed plumber.
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