Home Why does my toilet bubble? (3 possible reasons)

Why does my toilet bubble? (3 possible reasons)

After you flush the toilet, you hear a rumbling sound and start wondering what’s happening. A bubbling or gurgling sound is prevalent. This sound usually comes up if your plumbing system has a problem. It can be your toilet’s drain, vent, or mainline drain.

If the air is absorbed in the water, it creates bubbles. When the water pressure is too high, it forcefully enters the toilet bowl after flushing, creating air bubbles. Too much nitrogen or oxygen in water may also cause bubbles in the toilet. Usually, a clogged system is the main reason behind this issue. Toilet bubbles may cause several problems, including:

  • Loud gurgling sound
  • Poor flushing power
  • Overflow toilet
  • Bad odor
  • Water splash
  • Leakage

However, unlike other common toilet problems, this one is quite serious and cumbersome to deal with. It doesn’t matter if you’ve got a clogged toilet, a clogged drain line, or a clogged air vent. Most of these issues will consume most of your time, and you may need a professional plumber to fix them.

Why does my toilet bubble up when I flush? (Problem fixed)

If your toilet is currently producing a gurgling noise and wants to fix it, read our article to know what’s causing it and how to fix it.

  • Toilet clogging

This is one of the main reasons for toilet bubbling or gurgling inside the toilet bowl. Unlike other causes, you can quickly tell when your toilet is gurgling because of a clogged toilet. Excess tissue, large poop, toys, diapers, and condoms are some of the things that can make your toilet block.

With the right tools, fixing a toilet clog is very easy. Find out how to unclog your toilet with a few simple steps that we’re going to discuss below.  

Why does my toilet bubble?

How to clear the blockage?

You can unclog your blocked toilet with what you have at home. You can use some of the things you can use are a toilet plunger, toilet auger, snake drain, hot water, dish soap, or even vinegar and baking soda. A plunger is the most common tool in bathrooms to plunge the toilet. Use a no-clog toilet, as it has a wide flush valve that prevents a toilet from gurgling or bubbling.

However, it would help if you always started using the most straightforward method: using hot water, then trying a mixture of vinegar and baking soda. This method is not very messy and straightforward to apply. But if it fails, you should try a toilet plunger, auger, and toilet sewer snake. If all of these things fail, you should contact a professional plumber.

Clogged vent pipes

You may be hearing a bubbling sound when you flush the toilet because of a clogged vent stack. A block can create negative air pressure. The vent controls your plumbing’s negative air pressure and as well as releases exhaust gases. Vent pipes are usually vertical pipes that go through the roof.

Why does my toilet bubble?

Related article: Easy steps to fix a toilet handle by yourself

Since this pipe is meant for passing gases, it should always be open. Even water shouldn’t be allowed to flow through it. Hence, when the vent pipe is blocked, you will get negative pressure that causes toilet gurgles. Besides, you may also notice slow draining around the house or a smelly sewer odor.

If that’s what you’re experiencing, aside from having a toilet gurgling sound, you should fix the vent pipe. Proper inspection is needed as birds can build in the vent pipe, or even leaves may block air from flowing freely. Rodents can also interfere with the pipes and make a home in them.

No matter the reason, you should clear the vent pipe and have it functioning well again. You can use a garden hose to clear the vent pipe easily. Most of the time, it involves small fixes that you can handle.

How to unclog the vent pipe?

Start by climbing on your roof and checking out the state of the vent stack. This is quite challenging, especially for people who hate heights. Next, get rid of leaves or nests in the vent pipe. But if they are deep inside, you should not remove them as you can push them further. Instead, call a professional plumber to help you out.

If you successfully remove the clog, you should install a protective screen over the vent to prevent unwanted items from entering the vent pipe.

Mainline or Drain line clogs

If your toilet bubbles while flushing, check the central drain line is where all the drains in your home lead. This includes the drain from the bathroom, kitchen, laundry room, sink, and much more. The main drain carries waste and wastewater from your home to the city sewer system.

Why does my toilet bubble?

Some of the things that may cause the main drain line to have a problem are pipes separating, roots growing through the pipes, or pipe bending due to shifting.

Related article: How to drain water from the toilet bowl and tank?

The bad news is that you cannot fix any of the main sewer line problems. So if you’ve checked the vent stack and toilet drain system, but they don’t have a problem, you should call a plumber to inspect the main drain line.

Like a clogged toilet, the main sewer line may form air bubbles if it has a blockage. This is because the negative pressure forces air to return through the channel from where it came from your toilet or sink. As a result, you could get a bubbling sound after flushing the toilet.

How to fix it?

In this case, you cannot fix the running toilet by yourself. This is the work of the city sewer system to rectify. Therefore, you will have to call a professional plumber to check the issue for you. If your neighbor is facing the same problem, you can inform your municipal authority so that they can take the necessary action before it’s too late.

Final Thoughts

A bubbling toilet is a bad news for most homeowners. This is because all the possible causes of a bubbling or gurgling sound are quite cumbersome to deal with. Whether it’s a clogged toilet, a clogged vent, high water pressure, or a clogged mainline, you will have to spend some time and even get dirty in the process. You should fix your gurgling toilet in no time; otherwise, you might face a bigger water leakage problem.

Regardless, you can still fix the problems. But in the case of the mainline or drain line, you may have to call a professional plumber. Also, it may cost you several dollars to fix the problem. Like any other toilet problem, you should restore a toilet bubble quickly before it gets out of hand.

Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.


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