Why is My Toilet Bubbling When the Shower is Running

Are you familiar with your bathroom toilet bubbling and making a gurgling sound when you are taking a shower? Well, if you do, know that this is a hint of an underlying issue in your plumbing system that needs attention. Ignoring it might lead to more serious problems. 
Toilet, bubbling, shower.

In this article, we’ve talked about the most common causes and how to resolve the problem of maintaining a smoothly functioning plumbing system in your home.

Why Does the Toilet Gurgle or Bubble When Running the Shower or Sink?

If your toilet is bubbling and gurgling when running the shower or other fixtures like the sink, most probably, there is any blockage or partial blockage inside either your drain pipe or venting stack. Even the clogged municipal sewage line can cause this to happen in your toilet. 

When you experience this issue, addressing it promptly can save your plumbing system from more serious and costly problems.

Resolving this problem may require simple DIY work, or it could be complicated as well, which only a professional plumber can handle. In the following section, we will go into all the details about the possible causes and how they can be fixed.  

Understanding How Drainage Systems Work

Your household’s plumbing or drain system is designed to ensure efficient and smooth wastewater discharge. Before figuring out the causes of bubbling and gurgling in the toilet, understanding how the plumbing system works is important. 

Your home’s plumbing system consists of many parts. But to make it easy for you, we are explaining only a few entities that you need to know to understand the problem.

Waste Drain Pipes

Waste drain pipes are connected to all the fixtures of your bathroom and kitchen. They carry the water and waste all the way to the municipal drain. These drain pipes basically create a complex network of pipes that carry wastewater away to a sewage system or septic tank.

Venting or Vent Pipe

Venting is a crucial process in the plumbing system, responsible for regulating air pressure and ensuring the efficient drainage of wastewater.

It generally balances the negative air pressure by allowing fresh air into the plumbing system through the roof, following the wastewater that pushes the air downstream. This functionality prevents the water from bubbling up in the toilet and gurgling sound. Also, it ensures the proper operation or functionality of the p-trap, which basically prevents the sewer gas from entering your home. 

Overall, the venting pipe draws air through the roof and requires an unobstructed airflow for the drainage system to function correctly. If the vent pipe is blocked by debris, bird nest, or anything unexpected, you will surely experience a problem in your plumbing system. 

Common Causes of Toilet Bubbling and Solutions

Here are some common causes of the problem and effective DIY solutions.

Clogs in the Drain Pipes

A clogged or blocked drain is the most common cause of bubbling in a toilet when the shower is running. Both the shower and toilet are connected to a common drain pipe that carries wastewater. When the drain pipe becomes blocked for some reason, water and air become trapped inside the line. This situation creates water pressure that pushes air and water back into the toilet. That’s why you see air bubbles in the toilet after a running shower or when using the sink.

As water and air move backward, they create a gurgling sound in the P-trap, which is a U-shaped pipe located beneath sinks, toilets, and other fixtures in your plumbing system. Its primary function is to prevent sewer gases from entering your home and to maintain a water seal that acts as a barrier between the sewer system and your living space.

How to Fix

The solution for this issue is to plunge the toilet. In case you don’t know what plunging is, it is a common plumbing technique used to clear clogs in drain pipes. It requires using a tool called a “plunger” that needs to be pushed and pulled inside the toilet hole to remove or displace obstruction by creating a strong suction force. 

Before plunging, fill the toilet bowl with a bucket of water if it looks empty, as the water creates extra force during the plunging process. After that, insert the plunger into the drain hole of the toilet bowl and make sure the plunger cup at the front seals the toilet hole at the bottom properly. 

Now start pressing the plunger down firmly so the water doesn’t splash out, and then pull it up quickly. Continue repeating the process for 1 minute. After doing it for some time, check whether the water drains properly now. If it does, the clog may have been successfully cleared. If it doesn’t, you need to start plunging again.

If you fail to remove the clogs with a plunger, use a toilet auger, also known as a toilet snake, which is a specialized tool designed for clearing clogs within the toilet’s drain line. Insert the toilet snake into the toilet hole to push the clog and turn the handle clockwise, and the clogs will be removed. 

If it also doesn’t work, you can use chemical drain cleaner as a DIY last resort. However, you should handle the chemical very carefully and mindfully, or else getting professional help is safer and better. 

Blocked Venting Pipe

A venting pipe, also known as a venting stack, is crucial for your home’s plumbing system. We already explained that the venting pipe equalizes the negative pressure by allowing fresh air to enter the plumbing system when wastewater from various fixtures flows through the drain pipe.

Vent pipes are vulnerable to blockages caused by debris and various objects, as their open ends are particularly prone to accumulation. If the venting pipe is blocked by some buildups, the negative pressure creates siphonage in the p-trap and vacuum in the drainage system. This ultimately causes your toilet and other fixtures to bubble and make a gurgling sound. This can even allow sewer odors to enter into your bathroom and kitchen.

How to Fix

You need to simply unblock the obstruction inside the venting stack. To do it, you need to access the top of the venting stack by getting up on the roof. 

Once you climb up on the roof, inspect inside the venting stack and look for any accumulation with the help of a flush light. If there are any objects obstructing the pipe, insert a long plumbing snake into the opening of the vent stack. Carefully feed the snake down the vent stack while rotating it clockwise. This motion helps break up and dislodge the blockage and then pull it out to clear the debris from it. 

For extensive blockage, repeat the process several times to completely clear the venting stack. Once the blockage gets cleared, test plumbing fixtures in your home to ensure that the blockage has been successfully cleared and the water is draining properly.

Sewer Line Problems

If there is no blockage in the drain pipes and vent stack, this bubbling water and gurgling sound may arise from the municipal sewer system. To ensure it, you may contact your neighbors, as their drainage systems are also connected to the same sewer line. 

If the municipal sewer line is the culprit, your neighbor should also experience the same issue. Point to be noted: neither any DIY work nor professional plumbers can actually solve the problem. You need to call the proper authority to let them know the issue. As soon as you inform the right authority about the problem, they will promptly assess and resolve it.

However, to prevent sewer blockages and maintain proper sewage flow, avoid flushing non-biodegradable items such as wet wipes, sanitary products, and paper towels down the toilet. Always be sure to use biodegradable and septic-safe toilet papers, which break down quickly and are less likely to cause clogs in drain pipes, sewer lines, and septic systems. 

Poorly Installed Draining Pipes     

In newly built homes, members usually might experience this problem of toilet bubbling when the shower is running. The reason might be that the plumbing lines are not properly installed or vented. Through drain pipes, wastewater usually flows with the force of gravity. When the drain lines are poorly slopped or graded, the flow of water gets slow and sluggish. Even in some cases, water doesn’t move at all.

How to Fix

There is no quick DIY solution to address this issue. The resolution requires the expertise of a professional plumber, and it may come at a considerable cost due to the need for extensive wall work to access and diagnose the problem. However, before resorting to this option, it’s advisable to try all the previously discussed methods. Considering this inspection as a last resort is prudent


How Do I Know If My Water Pipe Is Blocked?

Answer: While there are many signs that may indicate the drain pipe is blocked, the most notable ones are water draining slowly from bathroom fixtures, gurgling sounds, and air bubbles in the toilet. In some cases, if the drain pipe is clogged, a persistent unpleasant smell comes from the drain or toilet hole.

What is the Main Reason for Pipes to Get Clogged?

Answer: The primary reason for a vent stack to get clogged is the buildup of debris, such as leaves, sticks, bird nests, or other foreign objects, in the vent pipe. The accumulation of these objects can block the flow of air and disrupt the proper ventilation of your plumbing system. 

Additionally, ice buildup in cold climates can also lead to vent stack clogs. Regular inspection and maintenance of your vent stack can help prevent such blockages and ensure the efficient functioning of your plumbing system.

Why Does My Toilet Burp When I Drain the Bathtub?

Answer: Your toilet burps when draining the bathtub for the same reasons it does when the shower runs. The possible causes include clogs in the venting pipe, drain pipes, or the sewer line. By reviewing the article, you’ll gain a comprehensive understanding of the details and potential solutions for this issue.


We’ve thoroughly covered and explained the functioning of the drainage system, simplifying the terms related to toilet bubbling and gurgling. Furthermore, you can find here various potential causes, from straightforward blockages to more intricate plumbing issues, and offered DIY solutions to troubleshoot and resolve these problems. 

To prevent your plumbing system from encountering such issues in the future, it’s crucial to be mindful of what you flush down your fixtures. Non-biodegradable items should be disposed of in the trash rather than poured down the sink or bathroom drain, as they can solidify and lead to pipe clogs.

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