If you’ve noticed your drains working a little slower recently, they could be cultivating a hidden garden below ground. According to the City of Sydney’s fact sheet 'Trees and their effects on drains and pipes' (PDF, 137 KB), tree roots are a common cause of blocked and burst pipes. Understanding how water leaks develop and what you can do to prevent them may help reduce your risk of needing to make an insurance claim.
Water leaks: Is there a secret bonsai garden below your sink?
Last updated on August 19, 2025
Discover how a hidden garden below your home could cause water leaks and what you can do to avoid them.
How tree roots affect pipes
Roots naturally search for water and nutrients, so any leaks can lure a tree towards a pipe’s weak spots or break right through them. Some tree species even develop hair-like fibres that can sneak into pipes with existing faults, such as leaking joints and deteriorating seals. Once inside, roots can grow to block entire lines. Blockages add more pressure on pipes, which may lead to a burst that can cause costly water damage.
Why burst pipes are more likely during the winter
Allianz Home Insurance claims data from 1 January 2024 to 30 June 2025 shows almost 29,000 claims for burst pipes, including water tanks and apparatus. Our data indicates, on average, claims for burst pipes increase during the cooler months. The main reasons for this are:
Tree root growth
You may think trees are going into hibernation mode in winter. But they actually focus their growth on roots, instead of branches and leaves. While they’re quietly growing, their roots will be seeking water sources, which could lead them to your home.
Cold causes cracks
Some parts of Australia get cold enough for water to freeze. When water freezes, it expands, creating added pressure that can potentially crack and burst pipes. That’s why plumbers tend to be even busier during particularly cold winters.
Rust thrives in the damp
Many parts of Australia experience damp conditions during the winter. The extra moisture can cause pipes to rust which may weaken them. If you live near the beach, the salty sea air may cause rust and corrosion that can affect your plumbing.
What happens when pipes burst?
In the worst-case scenario, burst pipes can send torrents of water through your home, soaking your furnishings and belongings. Even when you’ve turned off the water supply and called your plumber, the consequences can continue.
Indoor flooding
Your safety must come first. Depending on the severity of the flooding, you may need help from a licenced plumber, an electrician, and maybe even a flood restoration specialist. Burst pipes can leave you with a stressful and expensive clean-up on your hands.
Mould, mildew, and mozzies
Still water from damaged and leaking pipes can cause mould and mildew, if not dried out thoroughly and quickly. Once the leak has been fixed, it’s still important to check the area regularly for signs of water. You’re likely to notice that distinctive smell of mould. Any stagnant water may also attract mosquitoes and other insect pests.
Major structural damage
Water that seeps into your home’s foundations can cause cracks, which may lead to expensive structural damage and safety issues. Water damage can affect your walls and ceilings, and weakened foundations may cause subsidence.
Get ready for winter with these home maintenance tips
These handy home maintenance tips may help reduce the likelihood of water leaks and burst pipes.
Detect blockages early
Slow drains and gurgling toilets can be signs of obstruction. Always hire a licenced plumber to check your pipes if you suspect there’s something wrong. The sooner you identify the issue, the better.
Identify and replace old pipes
According to the City of Sydney’s
fact sheet ‘Trees and their effects on drains and pipes’ (PDF, 139 KB), old terracotta pipes are more susceptible to pipe leakage. If you have these pipes, consider replacing them with new PVC or UPVC ones, and use pressure seals. Contact your plumber to get advice, before they get too busy in the winter months.
Check flexi hoses
Flexi hoses, also known as flexi pipes, are rubber tubes wrapped in braided steel. You’ll typically find them under the sinks in kitchens, laundries, and bathrooms. They may be hidden but shouldn’t be forgotten as a damaged flexi hose can leak up to 1,500 litres of water an hour, causing significant damage.
Avoid blocking pipes
What goes down your sinks and pipes may seem to disappear into an endless black hole. But debris like grease, food scraps and even coffee grounds can easily build up and cause blockages. Taking care to avoid blocking your pipes with unnecessary household waste can reduce your chances of plumbing issues and water leaks.
Being mindful of the causes of water leaks and carrying out regular maintenance could help reduce the chances of an incident at your home.
For more information on how we can help you with your home insurance, contact our team.
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This article has been prepared by Allianz Australia Insurance Limited ABN 15 000 122 850 AFSL234708 (“Allianz”). In some cases, information has been provided to us by third parties and while that information is believed to be accurate and reliable, its accuracy is not guaranteed in any way.
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