Blocked Toilet: Causes & How to Fix It

Look, nobody wants to deal with a blocked loo first thing in the morning. But the good news is most blockages aren't actually that complicated. Nine times out of ten you can sort it out yourself with a plunger and maybe twenty minutes of patience, before you even need to think about getting someone else involved.

We'll run you through what's probably causing the clog, how to clear it without flooding your bathroom, the things people flush that they absolutely shouldn't, and when you've reached the point where a licensed plumber needs to take over.

What causes a blocked toilet?

Honest truth – something went down the toilet that really shouldn't have. That's what happens in most cases. Here's what we see causing the problem:

• Way too much toilet paper being flushed all at once, especially the thick multi-ply stuff
• Wet wipes, even those packets that say "flushable" on them – they don't break down like normal toilet paper does, not even close
• Things like sanitary products, nappies, cotton buds – these absorb water, swell up, and then catch on everything inside the pipe
• Kids' toys or random objects that someone's flushed without thinking
• A blockage further down the pipe, sometimes caused by tree roots getting into older drainage systems

When your toilet keeps blocking even though you're being careful about what goes in it, the problem is probably sitting deeper in the drain rather than right there in the bowl. That sort of thing we cover on our blocked drains page.

Before you start: stop the overflow

Right, so if the water's rising and looks like it's about to come over the edge – don't flush it again. That's just pouring more water into an already full bowl. Pop the lid off the cistern and hold that flapper valve down with your hand so it stops refilling, or you can switch off the isolation tap that's usually behind the toilet. Give the water a minute to settle before you start fiddling with anything.

How to clear a blocked toilet

Method 1: The plunger

A toilet plunger – the flanged type that actually fits into the outlet hole – is where you want to start.

• Make sure there's enough water sitting in the bowl to cover the head of the plunger. Chuck some in if it's looking a bit low
• Get the plunger positioned over the outlet and push it down so it forms a proper seal
• Push and pull with a steady rhythm, keeping that seal intact. Do this about 15 to 20 times
• On your last pull, yank the plunger away sharply – that's what breaks the blockage loose
• If it starts draining, give it a test flush. You might need to repeat the whole thing once more

Method 2: Hot water and detergent

Works well on softer blockages this one. Squirt a good amount of dishwashing liquid into the bowl, then tip a bucket of hot water in from roughly waist height. Not boiling though – just hot from the tap is fine. Let it sit there for 20 to 30 minutes. The soap helps everything slide through, and the warmth can loosen the blockage enough that a flush pushes it along. Boiling water is a bad idea – it can crack the porcelain.

Method 3: A toilet auger

When the plunger hasn't done the job, a toilet auger (sometimes called a closet auger) is your next option. It's basically a flexible cable that you feed into the outlet to reach whatever's stuck further down. Wind it in slowly until you hit the obstruction, then work it back and forth to break it up. Just be careful not to force it too hard – you can scratch the bowl.

What not to do

• Don't pour harsh chemical drain cleaners down the toilet. They mostly don't work on toilet blockages anyway, they can wreck your pipes and seals, and they make things dangerous for whoever comes to fix it after you.

• Don't keep flushing a blocked toilet, because you'll end up with water all over the floor.

• Don't use boiling water – the temperature difference can crack the bowl.

What you should never flush

There's a simple rule here: only the three Ps belong in your toilet. Pee, poo, and paper. That's it. Everything else goes in the bin.

When to call a plumber

Get a licensed plumber in when:

• You've tried plunging and augering a few times and it still won't clear
• More than one drain is slow or backing up – not just the toilet – which usually points to a main drain issue
• Water or sewage is coming up through other fixtures like the shower drain or floor waste
• The toilet keeps blocking over and over, which might mean tree roots or a damaged pipe

These are signs the blockage is sitting somewhere deep in the system that your tools just can't reach. A plumber can run a camera down there to see what's actually going on and clear it properly. In older parts of Perth especially, recurring blockages are quite often tree roots – we've got more on that in our guide about the signs of a blocked drain.

Why does my toilet block repeatedly?

A once-off clog is usually just something that shouldn't have been flushed. But when that same toilet blocks up again and again, the problem is almost certainly further down the line, and honestly no amount of plunging is going to sort it permanently. Here's what typically causes it:

• A build-up of stuff that shouldn't be there – wet wipes especially – that's been accumulating over months and slowly narrowing the pipe
• Tree roots that have found their way into the sewer line through cracks, which is pretty common in older Perth suburbs with clay pipes. The roots catch paper and waste as it flows past, so you get blockages that keep coming back
• A pipe that's partially collapsed or has a belly in it, where waste just pools instead of draining away
• An older low-flow toilet that doesn't push waste far enough down the drain, so stuff builds up just past the pan

All of these need proper diagnosis rather than you having another crack at it with a plunger. A drain camera shows you exactly what's happening down there, so whatever fix gets done actually addresses the real problem and not just the symptom you're seeing.

Keeping your toilet trouble-free

Prevention is way easier than dealing with a blockage. Stick to the three Ps, keep a bin next to the toilet so wipes and sanitary products never end up in the bowl, and go easy on the paper if your system tends to clog. Living in an older house with a history of root problems? A drain check every now and then stops small issues turning into a sewage backup situation. Bit of common sense goes a long way really.

Toilet still blocked after all that? Call our licensed Canning Vale plumbers to clear it fast and check there's nothing bigger going on in your drains.

Frequently asked questions