Top 10 Causes of Blocked Drains
(and How to Stop Them!)
Ever Had a Blocked Drain? You're Not Alone
Let’s be honest—there’s nothing worse than standing in ankle-deep shower water or dealing with a kitchen sink that won’t drain. Blocked drains are one of the most common household headaches in Australia, and if you’ve ever thought “Why does this keep happening to me?” — you’re definitely not alone.
Below are the top 10 causes of blocked drains we come across as plumbers across Aussie homes, along with tips to help prevent them from happening again.
1. Grease Build-Up
Grease from cooking might look harmless when warm, but once it cools down, it hardens and sticks to the inside of your pipes like glue. Over time, it narrows the passage until water can barely get through.
🧼 Prevention Tip: Wipe greasy pans with a paper towel and bin it—don’t pour it down the sink!
2. Fat (The Sneaky Cousin of Grease)
Fat doesn’t just come from the kitchen. Body fats from showers and bathwater can stick to pipes too. Mix that with food scraps or hair and you’ve got a solid mess that won’t budge.
🍳 Prevention Tip: Use a sink strainer and avoid tipping fats down the sink or toilet.
3. Hair
Hair is a major culprit in showers and bathroom basins. It binds with soap scum and creates tangled clumps that clog the pipes.
✂️ Prevention Tip: Install a drain catcher and clean it regularly. Also, avoid brushing or cutting your hair over the basin.
4. Toiletries
You wouldn’t believe how many toilets get blocked by those rim deodorisers or “clip-ons” falling in and getting flushed. Baby wipes and sanitary products are big offenders too—even if they say “flushable.”
🚽 Prevention Tip: Keep only the 3 P’s going down your loo—pee, poo, and (toilet) paper.
5. Tree Roots
In Australia, tree roots are by far the number one reason for recurring drain blockages. Roots are drawn to moisture and nutrients, and if there’s even a tiny crack in your pipes, they’ll sneak in and take over.
🌳 Prevention Tip: If you have large trees near your sewer line, get a plumber to camera-inspect your drains regularly.
6. Leaves and Garden Debris
Leaves fall into gutters and get washed into stormwater drains where they pile up and cause blockages—especially during autumn or after strong winds.
🍂 Prevention Tip: Clean your gutters and install leaf guards to stop debris before it enters the system.
7. Foreign Objects
We’re talking kids’ toys, stones, balls, tools, plastic wrappers—you name it, we’ve found it in pipes. Even small things like cotton buds or food scraps can cause big dramas.
👶 Prevention Tip: Educate the family (especially little ones) about what shouldn’t go down the drain. Use drain grates or covers for outdoor areas too.
8. Heavy Rain and Storms
A downpour can quickly overwhelm outdoor drains, especially if they’re already partly blocked. This can lead to water backing up and flooding your yard or even your house.
🌧️ Prevention Tip: Regularly check and clean stormwater drains and grates, especially before the wet season.
9. Broken or Collapsed Pipes
Older homes or those with shifting soil can suffer from cracked, sagging, or collapsed pipes. These create catch-points for debris and lead to ongoing blockages.
🔧 Prevention Tip: Have your drainage system inspected every few years—especially if your house is older or surrounded by trees.
10. Poor Installation or Workmanship
Sometimes the issue starts with how the pipes were laid in the first place—wrong angles, dodgy joins, or undersized pipes can cause constant backups.
📏 Prevention Tip: Always use a licensed plumber for any drainage or pipework. A cheap job now can lead to costly repairs down the track.
Final Thoughts
Blocked drains are a pain, but knowing what causes them and how to prevent them makes a huge difference. From tree roots to toy trucks, we’ve seen it all—and the good news is, most of it is avoidable with a bit of TLC and regular maintenance.
If you’re dealing with frequent blockages or suspect tree root damage, don’t wait until it’s an emergency—get a drain camera inspection and sort it out early.
Need help? Give your local plumber a bell. We’re here to keep your pipes clear and your home flowing smoothly.
THE DOCTOR GETS IT DONE