Bathtub Gurgles When The Toilet Flushes: How To Fix It

So, you flushed the toilet, and a strange gurgling noise is coming from somewhere. You’re finally able to isolate the noise, only to find out it’s coming from the shower. Well, that doesn’t make any sense, right? Why would flushing the toilet cause the shower drain to perform a solo? 

It actually makes sense, when you think of how the plumbing in your bathroom hooks up. Since the drains typically head out via the same pipe, issues with one part of the line can affect the rest. In some cases, the fix is quick and easy. Unfortunately, some cases may call for a plumber. 

Before you jump the gun and call in a plumber, make sure it’s not something simple. We put together a quick guide on potential fixes, so stick around to learn more!

Why Does The Shower Gurgle When I Flush The Toilet?

Why Does The Shower Gurgle When I Flush The Toilet

The bubbling, gurgling noise you hear from the bathtub drain when you flush the toilet can happen for a few different reasons. The three primary reasons include issues with the P-trap, air in the drain, and air coming out of the drain. 

Bathtubs have a P-trap in their piping system that is specifically designed to keep the pipe with a certain amount of water. If the piping system doesn’t have a P-trap, air can flow freely when the toilet is flushed, creating a gurgling noise. 

Another culprit of the noise may be air in the drain. Air vents regulate the amount of air moving through the pipes. When these vents are closed, it traps the air in the piping sound. The air in the water causes the gurgling noise from the bathtub.

Another common reason for the disconcerting noise is air coming out of the drain. When the the air vents are clogged, air forces itself through the drains. This results in a pressure difference that causes the burbling sounds. 

The plumbing vents provide the air that is necessary to allow the water in the pipes to drain. Contrary to what you may think, the vent stack isn’t a vent for odors. 

How To Get Rid Of The Gurgling Noise

There are a few different ways to address the issue of bubbling noises emitting from the drain when you flush the toilet. In some cases, you may be able to correct the issue yourself, but other scenarios may call for a professional plumber.

Plunge The Toilet


If there is air stuck in the pipes, you can use a plunger to help remove the air. This method is quick, easy, and only requires a few materials. Here is what you’ll need:

  • Duct tape
  • Plunger 

Start by duct taping the drains shut, including the shower drain, sink drain, and overflow drains. Make sure the tape covers the entire drain and creates an air tight seal. This ensures the force of the plunger remains within the pipe. 

Using a toilet plunger, plunge the toilet to loosen any obstructions in the ventilation system. Make sure the water in the bowl of the toilet completely covers the end of the plunger. Plunge the toilet for a few minutes, then flush the toilet and listen for the gurgling sound. 

If the noise persists, plunge the toilet a few more times. Plunging the toilet should help remove any air or other obstructions stuck in the drains or pipeline. 

Check The Ventilation System

If plunging the toilet didn’t work, check the ventilation system. Obstructions in the pluming vent lines may not be isolated to close by the toilet or bathtub. Instead, the issue may lie near the main stack opening on the roof.

Many times, when the ventilation system is the culprit debris falls into the vent opening. It collects in the elbow in the system, causing the issue. In rare scenarios, a bird or small animal may climb into these vents and build nests. 

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To correct the problem, you’ll need to clear out the air vents. You can do so using a garden hose or with a plumbing snake, just make sure it’s long enough to reach the obstruction and safely remove it. 

Some vent stacks have a screen covering the opening. The screen can become entirely obstructed by dirt and grime. If the vent stack has a screen, and it appears to be clogged, clean the screen to resolve the issue. 

Pipe Is Too Small

In some cases, the pipes may be too small. If you flush down too much toilet paper at once or things that shouldn’t be flushed, you may end up with similar issues. If nothing seems to help, you could increase the diameter of the pipe. 

While this might not be an expensive fix, it can be daunting, particularly if you don’t have any plumbing experience. We would recommend consulting a plumber before changing the pipe diameter, as it may be something simpler than this. 

Blocked Sewer Lines

Blockages can be a nightmare, especially for your sewer lines. Generally, this isn’t the culprit of the issue, but since it can be, we’ll discuss it. This problem usually is more complex than switching out pipes or plunging the toilet, and often requires the help of a plumber. 

If a blocked sewer line is the issue, you need to clear out the lines. It’s not as straightforward as pipe cleaning, so it’s typically best to have a professional handle it. 

Call A Plumber

In some cases, you may need to enlist the help of a professional plumber. If you’ve tried all of the above methods, but nothing seems to do the trick, it may be time to call a plumber.

2 thoughts on “Bathtub Gurgles When The Toilet Flushes: How To Fix It”

  1. Having a plumber route out your main drain or the breather vents costs over $400 now.
    Most elderly and people living on a fixed income can’t afford this type of charge. Does anyone know plumbers who offers discounts for this type of situation in the Baltimore metro area.


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