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How To Fix A Toilet That Bubbles/ Gurgles When Flushed 

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

It’s never a good sign when you start to notice your toilet beginning to bubble or gurgle after being flushed, and this could mean several different things.

Therefore, if you notice your toilet bubbling or gurgling it’s important to recognize and fix the issue straight away. 

Luckily for you, we have created a complete guide on how to fix a toilet that bubbles or gurgles when flushed.

This includes the signs to look out for, the reasons why your toilet may be bubbling or gurgling, and finally how to fix it. 

Why Does A Toilet Bubble/ Gurgle When Flushed?

Most toilet bowls are designed to keep some water at the bottom, this is otherwise known as the P-Trap (see also ‘S-trap VS P-trap‘).

This is to prevent any foul sewer smells or gasses from escaping your bathroom toilet (see also ‘Toilet Bowl Smells Like Urine‘), with the water acting as a barrier against it. 

If you notice your toilet bubbling or gurgling every time you flush it, this could be a sign that either your drain pipe or vent stack is clogged, or, likewise, it could mean that your septic tank is full.

This would create negative air pressure found inside the pipes that would be forced out through the toilet bowl in the form of bubbles bubbling from the toilet water, this is sometimes accompanied by a gurgling sound. 

This should be fixed as soon as possible as it’s usually a sign of a bigger problem waiting to happen.

This is because your toilet waste isn’t flowing out properly, causing a buildup of waste and debris in your drainpipe, this is why you may see bubbles or hear a gurgling sound from your toilet. 

If a toilet that is bubbling and gurgling when flushed is not fixed quickly, this could lead to a backup.

Typically, waste that is flushed down the toilet is channeled to a city’s sewer lines; however, if a backup occurs the water and waste will channel back through your pipes to your toilet, sink drain, bathtub drain, or any other drain connected to your house.

Therefore, it’s important to fix a bubbling or gurgling toilet quickly before it’s overflowing (see also ‘ How To Stop An Overflowing Toilet ‘).

How Does A Toilet Work?

For a toilet to function properly, a water tank is placed above the bowl, this is because toilets are dependent on gravity to operate correctly. 

When you flush your toilet, a large volume of water comes rushing down the tank into the toilet bowl, all within a short time.

This causes a pressure difference between the bowl and the drainpipe, which initiates the siphoning of the waste and water into the drainpipe. The waste is then channeled into the city’s sewer system. 

How To Fix A Toilet That Bubbles/ Gurgles When Flushed

A small amount of water comes out from the tank and settles into the bowl of the toilet.

This is the water you see at the bottom of your toilet bowl and is used as a barrier against sewer smells and gasses, preventing them from coming out into your house. 

Instead, the sewer gasses move up through the vent stack and are released into the air from the top of your house.

If the vent stack is blocked or clogged, the sewer gasses will have nowhere to go and escape; therefore, will go back into the toilet bowl water which is why you may see bubbling after flushing

How To Isolate A Toilet That Bubbles After Flushing?

Within a house, you will find a network of drain pipes throughout. Whether this is from the toilet, sink, bathtubs, or laundry rooms, these drain pipes are all interconnected and link into the main house drain pipe which then takes the waste and water out to the sewer line and then finally into the city sewer systems. 

Before you start fixing your bubbling or gurgling toilet, it’s important to make sure whether it is only your toilet drain pipe that is blocked or your whole house draining system. 

This can sometimes be tricky to distinguish. To make it easier for you, below you will find some common signs to look out for. 

1. Toilet Bubbles When Bathtub Drains 

Both the toilet drain and bathtub drains are connected to the main house drain pipe.

If you’re draining your bathtub and you start to notice your toilet gurgling, this could be a sign that your main house pipe drain is blocked. 

Turn on the bathtub faucet and let the water run down the drain. While you continue running the bathtub faucet, watch the inside of the toilet bowl.

If you notice the water bubbling, this would be a sign that the problem extends further than the toilet drain. 

On the other hand, if the bathtub water drains regularly without any bubbling from your toilet (see also ‘Why Does Your Toilet Bubble When The Bathtub Drains? An Easy Fix’) bowl, the problem is therefore only limited to the toilet drain.

This is a much easier problem to solve, as opposed to a blocked main house drain. 

2. Bathtub Drain Gurgles When Toilet Is Flushed

If a household’s main drain pipe is blocked and you go to flush a toilet, you may notice some gurgling sounds coming from your bathtub.

This is because the air will have to be displaced from the waste into the drainpipe as it has nowhere else to go and can’t flow out.

This displaced air will follow the channel with the least amount of resistance, which, in this particular situation, is the bathtub drainpipe.

Hence, this is why you may hear a gurgling sound from your tub since this is the air escaping from the drain. 

You may wonder why doesn’t the air just escape from the toilet bowl? Well, this is because the water in the bottom of your bowl acts as a barrier against any gasses or smells vacating your drain pipes. Therefore, the air will find a different way to escape. 

3. Toilet On A Septic Tank Bubbles When Flushed

If you notice your toilet bubbling when you flush it and you are using a septic tank, this could be a sign that your septic tank is either full or the drain pipe connected to the septic tank is blocked. 

How To Fix A Toilet That Bubbles/ Gurgles When Flushed

If your septic tank is full, all you need to do is empty the tank and your problem should be solved.

On the other hand, if your drain pipe connected to the septic tank (see also ‘What Is A Septic Inspection?‘) is blocked, you can easily resolve this issue yourself by unblocking the drain, or you could hire a plumber. 

4. Speak To Your Neighbors

Before you hire a plumber, it’s best to see if you can solve the problem by yourself as plumbers can sometimes be costly.

Although, what you can do is talk to your neighbors to see if they are having the same plumbing issues.

Sometimes, draining issues can affect a whole neighborhood. This is usually caused by a blocked city’s sewer line.

If that is the case, you would not have to take responsibility for fixing the problem, your city would.

Therefore, before you come to any conclusions, make sure to talk to your neighbors as all drain pipes are interconnected. 

How To Fix A Toilet That Bubbles Or Gurgles When Flushed?

If you have followed all the previous steps and you find that your whole house drains are blocked, not just your toilet pipes, the best thing to do would be to call a professional plumber.

Some people may attempt to fix this on their own; however, if not done correctly it could lead to more problems down the line.

These people usually advise you to do it on your own by removing the main sewer cleanout plug and snake the toilet from there. 

However, if your house drain pipes have not been working properly for a while, you could imagine the amount of household waste that has been piling up in your drains over time.

This would be a lot. So, not only would there be a great quantity of waste to deal with, but the waste inside the drainage pipes would also be under a lot of pressure. 

If you were to remove the plug by yourself, you would have sewage spilling and pouring all over your property.

Therefore, it’s best to hire a professional who knows exactly what they are doing. This will also save you money in the long run. 

On the other hand, if during your investigations you’ve concluded that it is only your toilet drain that is blocked, you can simply do this yourself. Below, you will find four different methods on how to do this. 

1. Unblock Your Toilet With A Toilet Plunger 

A toilet plunger features a long stick attached to a rubber cup that is designed to unclog toilets (see also ‘The Best Way To Unclog A Toilet When Nothing Works‘).

It does this by, essentially, creating a pressure difference between the clog and the bottom of the clog where the pressure is less than the exercised pressure, resulting in the block being sucked back inside the drain pipe.

It would also work by sucking the existing block inside the toilet bowl. To do this, you should invest in a good quality plunger that will fit securely inside the bottom of the toilet and create a seal, this will ensure that no air can escape. 

When plunging the toilet, make sure that your plunger is secured to the bottom of the toilet.

From there, you can begin pushing and releasing the plunger until the block has dislodged.

Hopefully, by doing this enough times you will be able to resolve the issue, and your toilet will no longer be bubbling.

To make sure the issues have been resolved, flush the toilet to check for any bubbles or gurgles.

If that is successful, you have unblocked your toilet all by yourself! Meanwhile, if the block persists, check out the other methods below. 

2. Unblock Your Toilet With A Toilet Auger 

A toilet auger, otherwise known as a plumber’s snake, features a long cable with a head and a cranking handle that is used for unclogging toilets.

As its name suggests, this resembles a snake. It unclogs a toilet (see also ‘How To Unclog A Toilet When Nothing Works‘) by breaking up the clog into smaller pieces, or by pulling the clog out whole.

Unlike the plunger, the toilet auger goes straight inside the toilet drainpipe to tackle the problem directly, if it is in range to do so.

Typically, toilet augers are between 3 to 6 feet long; however, professional plumbers can use motorized toilet augers that reach more than 100 feet in length!

If you are having trouble trying to reach the clog, it’s best to hire a professional as the clog may be too deep and they may need to take off the toilet to reach it. 

However, most of the time, you shouldn’t face any issues with a standard toilet auger.

To check if the blockage is resolved, simply flush the toilet to see if the bubbling continues.

If it doesn’t, the clog has been dislodged! However, if your problem is persisting, there is one more method for you to try next. 

3. Unblock Your Vent Stack 

The last thing to consider is your vent stack. If blocked, sewer gasses will get stuck inside your vent stack resulting in a build-up of negative air pressures.

When the pressure reaches its limit and it’s more than the toilet bowl can contain,  it will start escaping through your toilet water which is why you may see bubbles or hear gurgling sounds. 

To unclog your vent stack, all you need to do is use a ladder to climb up to the top of your roof with a garden hose.

Check and see if you can unblock the clog using your hands, usually, this will only be leaves, nests, or debris.

Otherwise, if you can’t, use the garden hose, and pour some water down the vent stack. This will help wash away any blockages. 

4. Call A Plumber 

If all else fails, you can always call a plumber. With their vast knowledge and experience, they should be able to easily help you dislodge any blocks you may have in your drains.

If unsure, it’s always best to phone a professional, rather than try different methods that could result in further damage. 

Final Thought

Sometimes, a toilet that bubbles or gurgles can either be an easy fix or very complicated to mend.

If left untreated, this problem could escalate and you could be left with even more damage.

Therefore, it is important to resolve a bubbling toilet as soon as you detect it.

Hopefully, this guide has informed and helped you fix a toilet that bubbles or gurgles.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases. When it comes to dealing with clogged drains, many homeowners turn