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Why Is My Toilet Bubbling When The Shower Is Running?

While taking a shower, the last thing you anticipate seeing is a bubbling toilet. Although the plumbing in your bathroom may appear flawless from the outside, there might still be some internal flaws. A toilet that bubbles up when the shower is running is an indication that there is a hidden problem.

So, why is my toilet bubbling when the shower is running? The most common reason is an obstruction in the plumbing vent system. Because of the obstruction’s interference with airflow and pressure imbalances, air escapes through the toilet bowl, which causes bubbles.

To restore appropriate airflow and resolve the toilet bubbling problem, it is necessary to check and fix the vent system. Let’s embark on this plumbing adventure, where you will know details about the reasons behind this plumbing problem and ways to fix this.

Why Is My Toilet Bubbling When The Shower Is Running?

Here are 5 major reasons why a toilet may bubble up when the shower is running: 

Drainage System Obstruction

A clogged or partially blocked drainage system is the most common reason for toilet bubbling when the shower is running. Your home’s plumbing is linked, and the same pipes carry wastewater from different fixtures like the shower and toilet.

The water has a difficult time flowing through when there is an obstruction in the line. Because of this, air pockets may develop and cause gurgling or bubbling in the toilet.

Issues with Ventilation

Another possibility is that your plumbing’s ventilation system is malfunctioning. Plumbing vents are intended to adjust air pressure in the drainage system and expel sewage gasses. These vents cannot efficiently carry out their duty if they are blocked or obstructed.

As a result, when water is drained down the shower, the air needs to find a different path to leave.  When it can’t find a different path, it might end up in the toilet, where it could cause bubbling.

Partially Blocked Water Supply Valve

Another potential issue is a partially blocked water supply valve for the toilet. The water flow to the toilet is restricted if the valve is partially closed.

The pressure drops when you turn on the shower because the demand for water rises. Air may be drawn into the toilet bowl as a result of the lower pressure, which can create bubbles.

Faulty Plumbing System Design

Toilet bubbling may occasionally be a result of poor pipe sizing or insufficient plumbing system design. Hence, air can build up, and pressure imbalances can occur if the pipes are too small.

It can also happen if the system is not equipped to manage the amount of water being drained. This may result in bubbling, which is caused by air bubbles rising through the toilet water.

The problem with Main Sewer Line

A blockage or damage to the main sewer line could indicate a more serious problem. The flow of wastewater may be hampered if the main sewage line gets blocked.

As a result, pressure can build up when water is removed from one fixture, like the shower. This causes the toilet to bubble as the air looks for a way to escape.

toilet bubbling when the shower is running

How to Prevent Toilet Bubbles While Using the Shower?

You can prevent toilet bubbles by following these steps:

Step 1: Check for Obstructions in The Drain And Toilet

  • Start by looking for any obvious clogs in the drain and toilet.
  • Use a plunger to remove any clogs in the toilet.
  • If the bubbling continues, try clearing obstructions from the drainpipe using a plumbing snake.

Step 2: Shower Drain Cleaning

  • Take off the shower drain cover to inspect it for any buildup of hair or debris.
  • Examine the drainpipe with a flashlight while wearing gloves.
  • Use a plumbing snake or a solution of baking soda and vinegar to clean any obstructions you find.

Step 3: Check the Plumbing Vents

There could be a problem with the plumbing vents if the bubbling persists. Ascending to the roof, examine the vent pipes for any obstructions brought on by leaves, objects, or bird nests. To restore appropriate airflow, gently remove any blockages you encounter.

Step 4: Ensure Supply Valve Is Fully Open

  • The water supply valve is located behind the toilet; check it.
  • Turn it in the other direction to make sure it is fully open. The toilet may bubble while the shower is running due to a partially closed valve restricting water flow.

Step 5: Use Drain Cleaner

Use a professional drain cleaner if you think there may be organic debris or residue buildup in the pipes. In order to prevent any harm to your plumbing system, carefully follow the directions that come with the device.

Check the toilet and shower for any changes after trying these techniques. It’s advised to call a professional plumber for a complete investigation and repair if the bubbling continues.

Why You Should Avoid Having Toilet Bubbles During Shower?

As mentioned above, faulty plumbing ventilation is one of the causes of toilet bubbles. Your roof’s vertical pipe connects to the drain and sewer pipes in your home.

  • The vent pipe permits the safe passage of air and gas without impeding water flow through your drains. Vent pipes assist your house in getting rid of sewage odors by letting fresh air flow through your pipes.
  • Sewage gasses tend to escape through your drains if your vent line becomes clogged. Hence, the bubbling starts during the shower.

If you don’t address this issue, it can create issues like headaches, drowsiness, and nausea during the shower.


We will address some of the commonly asked questions by our readers in this part.

Q: Why Is My Toilet Bubbling When The Washing Machine Is Running?

There may be a ventilation problem in your plumbing system if your toilet bubbles when the washing machine is operating. Because of the washing machine’s high water consumption, pressure changes may occur.

Q: Why Do Toilets Overflow When the Shower Is Running?

Mostly a  clog in the drain line is to blame for toilet overflow when the shower is on. The amount of water in the plumbing system is increased by the flow of the shower. So, if there is a blockage in the drain line, it may cause water to backflow and thus the toilet to overflow.

Q: Why Does My Toilet Flushes Slowly And Gurgle?

The gurgling sound is caused by air bubbles escaping through the water. The delayed flush indicates that water is having trouble moving through the pipes. Numerous things, such as built-up trash, mineral deposits, or tree roots encroaching into the sewage pipe, might result in a clog.


So, why is my toilet bubbling when the shower is running? Well, the bubbles in your toilet during a running shower reveal a plumbing problem waiting to be fixed. Reasons can vary from blocked drain lines to faulty ventilation systems.

Your bathing experience could be compromised if you ignore this problem. In the long run, it may also have an impact on your health. Thus, if you’re a DIY enthusiast, you can fix it yourself by following the instructions given in this article. However,  you can seek expert assistance if you have never repaired a plumbing system before.