Gurgling Sink When the Toilet is Flushed – Causes & Solutions

Written by

Paulk Webb


Freddie J. Hagopian

Saveourwaterrebates is reader-supported. When you buy via our links, we may earn a commission at no cost to you. Learn more

gurgling sink when the toilet is flushed

Toilets are commonly used plumbing fixtures at home so a gurgling sink when the toilet is flushed can be troublesome.

Now, if you are here because you want to ask, “How do I stop the gurgling when I flush the toilet?” , good news because there’s a ton of tips waiting for you. So keep reading.

What’s a Gurgling Sound in Sinks?


Here are common scenarios. You flush the toilet, the sink makes noise or the tub gurgles. It’s also possible the toilet is slow to drain and gurgles. In most cases, sink gurgles but drains fine.

You might also be thinking, when I plunge the toilet, the sink gurgles,what’s this weird rumbling sound?

Whether you hear the sound randomly or immediately after flushing the toilet, you might recognize the sound resembling a bubbling or gurgling noise like water rapidly moving and splashing.

The gurgling sound in the sink is typically caused by trapped air in the plumbing system that escapes through the water in the toilet bowl.

Causes: What’s Behind Your Gurgling Sink?

It’s quite a nuisance when you flush the toilet and the sink gurgles but it spells more trouble when you know nothing about what is causing your drain to gurgle.

1. Drain Clogs


Clogs in the pipe are typically caused by hair, dirt, soap residues, oil and grease. The blockage traps the air in the plumbing system which results in the drain gurgling.

2. Blocked Vent Stack


In order for water to flow, there must be enough ventilation in the drain pipes and lines.

Leaves or any trash blocking the vent system create negative pressure, disrupt the flow, and ultimately stop your plumbing system from functioning.

Why does the toilet gurgle when the shower is running?

One, your toilet and shower connect to the same drain line and vent stack. Two, there’s a clog in either the drain line or the vent stack which forces the air up or down the toilet.

3. Blocked Sewer Lines


Blockage in the main sewer line, which connects all your drain pipes, is trouble. It indicates multiple drains in your home are clogged.

What’s causing this blockage? More likely, the pipes are deteriorating from being exposed to strong chemicals, accumulation of trash blocking the pipes, tree roots infiltrating the pipes, or soil shifting that leads to soil breakage.

How to Make the Sink Quiet: A Simple Guide


The odd gurgling sound seems minor at first notice but do not ignore that noisy sink drain.

Next thing you know, it’s not just a simple gurgling sound when the toilet is flushed. Soon you had to deal with a serious damage in your plumbing system. What a hassle it can be!

Not to worry because there are ways to fix it.

Another important note. While you can fix it right away by yourself for good reasons, it’s also not a bad idea to call a professional plumber. Especially when it is necessary to repair some pipes or use specialized equipment.

What You Will Need


  • Plunger
  • Brush or plumbing snake
  • Ladder
  • New air admittance valve (AAV)
  • Garden hose
  • Sewer auger
  • Hydro jetting machine

Here’s a list of expert-recommended hacks on how to stop your gurgling sink.

1: Plunging the Sink


Before anything else, make sure you seal the sink drain tightly by placing the plunger cup over it. Maintain approximately an inch of standing water in the sink. Push and pull the plunger in an up-and-down motion for half a minute.

After plunging the bathroom sink and covering it, the next step is to plunge your toilet.

Open the sink drain and try flushing the toilet. Repeat the process if you can still hear the gurgling.

You might consider trying other methods if this one doesn’t work.

 2: Cleaning the Roof Vent Stack


This is no simple task. For starters, you’ll have to use a ladder and go up on your roof and locate the main vent stack.

Inspect the vent stack and see if there are blockages or obstructions. Using a long, flexible brush or plumbing snake, remove any debris from the vent stack.

Use a garden hose to clear out the vent pipe. If there’s a huge blockage and the water keeps falling out, it’s best to use a sewer auger.

If this method looks too complicated, getting help from a plumber will save you time and money.

 3: Replacing the Cheater Valve/AAV


First thing to do is shut off the water supply to the sink. You will find the cheater valve or air admittance valve (AAV) typically under the sink.

Loosen the screws of the cheater valve and disconnect it from the plumbing system. Then, install a new AAV.

Then, turn on the water supply and check if your toilet works well again.

4: Cleaning the Sewer Lines


If none of the first 3 methods work for you, you clearly need a professional plumber to fix your pipes. They use specialized equipment like hydro jetting to clean sewer lines.

Bonus Quick Fix: In case of a gurgling kitchen sink, an easy and cost-effective solution is by using chemicals that can remove drain buildups.

Essential Tips to Avoid Gurgling Noises


You might think it’s a hassle to get gurgle out of the sink. So a golden rule in home maintenance you should know, prevention is key!

#1. Keep your drains clean and clear

Do a simple cleaning once a month. It could be as simple as using baking soda, vinegar, or hot water during cold weather to do the magic for you.

Make it a yearly routine to thoroughly clean your drains by removing basin stoppers and clearing away hair and soap scum buildup.

#2. Install aerator on the faucet

An aerator on a faucet minimizes the occurrence of air bubbles in the plumbing system, hence effectively preventing the gurgling noises.

The good news is, aerators are relatively cheap and easy to install.

#3. Provide ventilation to your plumbing system

It’s important that your plumbing system has adequate ventilation. This will help air to flow properly and prevent pressure buildup.

#4. Monitor water level and pressure

Too much or too little water has effects when you flush the toilet. Check your water level regularly.

High water pressure puts a strain on your plumbing system and eventually creates the gurgling noise. A pressure regulator can make a huge difference.


Say goodbye to a gurgling sink when the toilet is flushed by trying out the 4 effective methods on how to fix your toilet problems. Don’t forget to follow the essential tips we provide to avoid gurgling noises.

If you can identify what’s causing the gurgling and decide you will take charge of unclogging the sink, there’s an easy-to-follow guide made just for you. Otherwise, you can never go wrong with contacting a professional plumber to help you out.

Find out which solution works best for you and your home.

5/5 - (2 votes)