How to Unblock an Overflowing Toilet – Expert Guide

If your toilet is overflowing and won’t flush properly, you need to act fast. Not only is it messy and unpleasant, but a blocked toilet can also lead to serious plumbing issues if left untreated. In this guide, we’ll show you exactly how to unblock an overflowing toilet safely, using methods that work, and we’ll tell you when it’s time to call in a professional.

Why Toilets Overflow

A toilet typically overflows because of one of the following:

• Blockage in the trap (the S-shaped bend inside the toilet)

• Blocked soil pipe leading away from the toilet

• Foreign objects flushed by mistake (wet wipes, sanitary products, toys)

• Build-up of toilet paper causing a partial or complete blockage

Step-by-Step: How to Unblock an Overflowing Toilet

1. Stop the Water Flow

Before anything else, prevent further flooding:

• Turn off the isolation valve (usually found behind or next to the toilet).

• If you can’t find it, remove the cistern lid and lift the float to stop water entering.

2. Protect Your Bathroom

• Put down old towels or newspaper to absorb any spillage.

• Wear rubber gloves for hygiene and safety.

3. Use a Toilet Plunger

A flange plunger (specifically for toilets) works best:

1. Place it over the toilet outlet, ensuring a tight seal.

2. Push and pull firmly for 20–30 seconds.

3. Repeat until the water starts to drain away.

4. Try a Drain Unblocking Solution

If plunging fails:

• Use a drain-safe unblocker designed for toilets.

• Follow the instructions carefully and allow time to work before flushing.

5. Use a Toilet Auger (Plumbing Snake)

For stubborn blockages deeper in the pipe:

• Insert the auger into the bowl and turn the handle to break up or pull out the blockage.

When to Call a Professional Toilet Unblocking Service

If the toilet is still overflowing after trying the above methods, the problem may be in the main drain or sewer line. At this stage, DIY methods won’t work, and forcing it could cause serious damage to your pipes.

At GSB Drainage, we provide 24/7 emergency toilet unblocking in Southampton and surrounding areas. With specialist high-pressure jetting and CCTV drain surveys, we’ll find and clear the problem fast, with no call-out fee.

How to Prevent an Overflowing Toilet in the Future

• Only flush toilet paper — nothing else.

• Avoid excessive paper in one flush.

• Keep bathroom bins available for sanitary products and wipes.

• Have your drains inspected annually if you’ve had repeated issues.

Final Word

Knowing how to unblock an overflowing toilet can save you from stress and expensive repairs. If you’ve tried everything and your toilet is still blocked, it’s time to bring in the professionals.

Call GSB Drainage now on 07738 181472 for fast, friendly, and affordable toilet unblocking in Southampton — we’re here 24/7.