5 Common Causes of a Blocked Toilet and How to Fix It

A blocked toilet is something no one wants to deal with, yet it’s a common household issue that can happen at the worst times.

Whether it’s an unexpected clog that causes water to back up or a stubborn blockage that just won’t budge, knowing the cause is key to solving the problem.

Often, it’s something as simple as too much toilet paper or flushing the wrong items, but sometimes it could be a more serious issue like tree roots in the sewer line.

In this blog, we’ll cover the five most common causes of a blocked toilet and, more importantly, how you can fix them quickly and easily. With the right knowledge and a few practical tips, you’ll be prepared to handle this messy situation like a pro.

1. Too Much Toilet Paper

Using too much toilet paper is one of the most common causes of a blocked toilet. While toilet paper is designed to break down in water, large amounts of it can create a clog before it fully dissolves.

This often happens when you flush a big wad of toilet paper all at once, causing it to get stuck in the toilet trap or the pipes. When this happens, water may struggle to drain properly, and you’ll notice it rising in the bowl instead.

The good news is, this is usually an easy fix. Start by using a plunger to create suction and dislodge the blockage. If that doesn’t work, a plumbing snake or auger can help break up the clog.

To prevent future blockages, try using less toilet paper at a time and flushing in smaller amounts. If you’re still having issues, consider switching to a thinner, more easily dissolvable toilet paper. Small changes in habits can make a big difference in keeping your toilet clog-free.

2. Flushing Non-Flushable Items

Flushing non-flushable items is a leading cause of toilet blockages. Many products are labelled as “flushable”, but that doesn’t always mean they break down properly in your plumbing.

When these items get stuck, they create clogs that can lead to bigger plumbing problems.

Here are some common culprits:

• Baby wipes and wet wipes: Even “flushable” wipes don’t break down like toilet paper.
• Feminine hygiene products: Tampons, pads and other hygiene items expand in water, causing major blockages.
• Paper towels and tissues: These don’t dissolve in water and can easily get stuck.
• Cotton balls and swabs: They are small, but they clump together and create tough clogs.
• Dental floss: It doesn’t dissolve and can wrap around other debris in the pipes.

To fix a blockage caused by non-flushable items, try using a plunger to create suction and dislodge the clog. If that doesn’t work, you may need a plumbing snake to break up the obstruction. To prevent future issues, always dispose of these items in the trash, not the toilet.

3. Clogged Toilet Trap

The toilet trap is a curved section of pipe located inside the toilet, designed to prevent sewer gases from entering your home. However, it’s also a common place for blockages to form.

When you flush items like too much toilet paper, hygiene products, or other debris, they can get caught in the trap, creating a stubborn clog. If the water in your toilet rises when you flush or drains slowly, the trap could be the culprit.

To fix a clogged toilet trap, your first line of defence is a plunger. Place the plunger over the drain hole and use firm, quick pumps to create enough suction to dislodge the blockage. If that doesn’t work, you might need to use a plumbing snake or auger, which can help break up the clog deeper in the pipe.

To avoid this issue in the future, make sure only flushable items go down the toilet, and flush in smaller amounts to keep your toilet’s trap clear and functioning properly.

4. Obstructed Plumbing Vents

Your plumbing system relies on vents to allow air to flow freely, helping water and waste move through the pipes smoothly. When these vents become blocked, it can lead to slow drainage and frequent toilet clogs.

Here are some signs your plumbing vent might be obstructed:

• Gurgling sounds: If you hear gurgling after flushing, it could be air trapped in the pipes.
• Slow drainage: Water drains slowly from the toilet or other fixtures in your home.
• Frequent clogs: Recurrent toilet blockages, even after clearing them, may point to vent issues.
• Bad smells: Sewer gas smells in your home could indicate a blocked vent preventing proper airflow.

Fixing an obstructed plumbing vent often requires professional help, as the vent pipes are typically located on your roof. A plumber can clear debris, like leaves or nests, that might be causing the blockage.

To prevent future vent obstructions, regularly check your roof for potential blockages and keep the vent pipe clear of debris, ensuring your toilet drains properly without recurring clogs.

5. Tree Roots Infiltrating Sewer Line

Tree roots can be a surprising cause of toilet blockages, especially if your home’s sewer line is older or made of clay. Roots naturally seek moisture, and small cracks in sewer pipes give them an entry point to infiltrate and cause significant blockages.

Here’s how to recognise and address this issue:

• Slow-draining toilet: If your toilet drains slowly or backs up often, roots could be restricting the flow.
• Recurring blockages: If clogs keep coming back despite your efforts to clear them, tree roots might be the cause.
• Gurgling sounds: This can happen when roots are obstructing the sewer line, trapping air in the pipes.
• Lush patches of grass: If certain areas of your yard are unusually green, tree roots may be thriving off a broken sewer line.

Fixing tree root blockages requires professional intervention. A plumber can inspect the sewer line using a camera to confirm root infiltration.

They may use specialised root removal tools or hydro-jetting to clear the pipes. In severe cases, part of the sewer line might need repair or replacement to prevent future problems.

Be Mindful of What You Flush

Dealing with a blocked toilet is never fun, but understanding the common causes can help you fix the problem quickly and prevent it from happening again.

Whether it’s too much toilet paper, non-flushable items, or something more serious like tree roots in your sewer line, there’s usually a straightforward solution. In many cases, a plunger or plumbing snake can do the trick, but sometimes it’s best to call in a professional, especially if you suspect bigger issues like obstructed vents or damaged sewer pipes.

By being mindful of what you flush and staying on top of plumbing maintenance, you can keep your toilet running smoothly and avoid the hassle of future blockages. If in doubt, don’t hesitate to reach out to a plumber for expert advice.

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