Sink Gurgles When Toilet Flushes – What Can I Do?

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You walk into your bathroom and you finish using the toilet normally, but when you flush it you hear a gurgling noise coming from your sink?

What could be the cause of this new sound? 

The first couple of times you hear this noise you might not think much of it, but if you ignore it for a while it can become very troublesome.

After a while, you will notice that water is draining slower and slower. Other than that, gases from the sewer, like methane and hydrogen sulfate can enter your home and cause issues like sinus infections.

Besides, the smell emitting from these gases is something you will definitely want to avoid, especially it spreading outside the bathroom to the rest of your home.

Like with every problem that comes from clogged sinks and pipes, the solutions for this one are pretty easy if you follow the instructions. This particular problem is not harder to solve than any other, and you won’t have to spend a lot of money to do it yourself. Let’s take a look at how to do it.

Sink Gurgles When Toilet Flushes

Why does your sink gurgle when toilet flushes?

Let’s first cover why this happens so we can understand how to solve it. Imagine pouring juice into a glass very fast and the sound that makes – gurgle, gurgle, gurgle. That’s what this will sound like.

A sink gurgles usually because blockage is formed in the drain or in the vent pipe. This blockage can consist of hair, grease, dirt, leaves and so on, you wouldn’t believe what stuff can be the cause of your gurgling sink headaches.

Sometimes a gurgling sink can be the consequence of a damaged pipe. Although this situation is rare, it’s worth checking out whether your pipes are in good shape or not.

If you hear this sound and it’s winter season, the problem is caused by freeze-up in condensation in the main vent pipe. We always recommend that in winter you don’t attempt any housework that involves going on the roof if you are living in an area with snow. Instead, opt for calling a plumber.

Gurgling Sink When Toilet Flushed

All in all, this problem occurs when the pipes don’t have proper ventilation, because the gurgling sound is the sound produced from the P-trap (a pipe that is shaped like the letter P) when air passes through it.

A logical conclusion from this would be that this problem can be fixed by simply cleaning your pipes, but this is easier said than done if you’re doing this on your own without any directions to follow.

How to fix a gurgling sink

The more tools you have the more options for fixing a gurgling sink are available for you. Here are the tools you will want to have with you before going further:

  • a plunger
  • ladder
  • an extra valve
  • an auger
  • garden hose

Of course, it’s not necessary to have all of them, so don’t panic if you only have one or two. This just means that you will less available options to do this yourself.

1. Put a plunger to good use

Most people have used a plunger sometimes already in their life, so this solution shouldn’t be too hard for most folks.

First, seal the drain of the sink to make sure that plunging will be done correctly. Once you’ve done this, then you can plunge the toilet.


Press the plunger hard down and pull it up several times until you feel the blockage is removed and the air has gone through the sink drain.

Try flushing the toilet and see it the sink still gurgles. If it does, just repeat this entire process again and see if it’ll work then.

2. Replace a valve

Below your sink, you can find a valve which if you replace can be your solution.

Usually a plumber does this but honestly, there is no need to spend the extra money on calling a professional when the switch to a new valve is quite simple and cheap, so you can do it yourself.

3. Use a chemical solution

If you’ve failed to prevent a clog from being formed and there is already a solid mass formed of hair, food, grease and so on, then consider using a chemical solution

Although these can be toxic (but not always), just follow instructions they come with and you will be completely okay.

Simply pour a chemical solution down the drain and let it sit there for a while so it can do its magic and voila – enjoy your quiet sink!


4. Pour boiling water down the vent pipe

This can be handy in winter when closure happens because of frost.

The vents happen to freeze completely and then the system can’t have normal air flow, causing the sinks to gurgle. 

You can pour boiling water through the vent pipe to heat the system and help it get back on track.

5. Go on the roof

If a blocked vent pipe is the cause of the problem that means that the air from the pipe can’t escape through the vent itself but will look for the closest hole, which usually happens to be the sink you last used.

All main plumbing pipes are connected to the vent pipe which is commonly placed on the roof.

From the roof nests and leaves can build up and will need to be cleaned up. This is the reason why usually plumbers go unblocking vent pipes, but if you’re comfortable with climbing up on the roof of your house and it’s safe to do so, you can do it on your own.

Never attempt this during winter if snow and ice are on the roof, and always put on running shoes so you don’t accidentally slip.


First, climb the roof with a ladder and check the opening of the main vent. Check for bird nests, leaves, dirt or anything else that shouldn’t be there.

The funny thing is that there have even been examples of spider webs being the cause of blockages because they can collect material and form a solid mass. If it’s there, simply clean it.

Now you can spray down the vent with a garden hose and see if the water runs through as it should. If that’s not the case and the water is backing up you should be convinced that a blockage exists. To clear it you can use an auger.

6. Do it with an auger

If, however, you want to physically fix your sink and stop it from gurgling you can use an auger – a flexible metal wire which can go to the depths of pipes and breaks blockages.


This tool is not strong enough to damage the pipe system but has enough power to break the clog, so it’s a very safe option which we recommend for you to try.

In Conclusion: Gurgling Sink When Toilet Flushed

If none of the mentioned solutions worked for you then it’s time to call the plumber. In this case, you’re probably going to need new pipes or your drain system may be ineffective, so only a plumber can help you with this.

There is no shame in admitting that housework is not one of your strengths and calling someone who is a pro at this.

If you are not comfortable with executing any of the solutions or you still think that having someone do it instead is worth the money, remember that there is a good reason why plumbers exist.

Waiting for this problem to be solved on its own won’t do you any good. The sound itself is a sign that something is wrong and that you should address it. All it takes for you to be safe from sewer gases is a little time and a bit more will.

With these solutions, we are sure that you’ll overcome this challenge and enjoy your silent sink with normal water flow!