Noisy Toilet Flush: Foghorn, Vibrating and Groaning

noisy toilet flush

Last updated: January 31, 2022 at 10:50 am

Toilet flushing noises are very common in most toilets. Some toilets produce pronounced sounds or noises than others. It is normal to hear these sounds, but could they be something to worry about? The answer is often no.

However, some toilet flushing noises may be serious and should be inspected or listened to by an experienced plumber. But the reason why you hear toilet flushing noises and what causes them can help you understand them better.

This article describes common toilet flushing noises, as well as some which you should not ignore.

Are Toilet Flushing Noises Anything to Worry About?

Flushing noises are a common phenomenon in older homes. Older toilets and plumbing systems tend to gurgle and flush differently from new toilets and plumbing systems.

Toilet flushing sounds are usually caused by air escaping from the fill valve or siphon tube of the toilet tank. This usually occurs when the tank is filling but can also be caused by the toilet running into a full bowl.

Toilet tanks fill in two ways:

  • gravity filling
  • pressure-assisted filling

Older toilets use gravity for filling, which means that once the water level reaches a certain height, it will stop until sufficient force is applied to push more water into the tank. This causes a pause in filling and can cause a gurgling sound.

Over time, mineral deposits can also build up on components within the tank, causing parts to stick together and restricting water flow. Newer models use anti-siphon valves to prevent this.

Modern toilets use pressurized filling, which means that water will continue to fill until no more room is left in the tank, causing a constant flow of water into the bowl.

Toilet flushing sounds can also be caused by the flow rate of your toilet’s flush mechanism. Some toilets have low-flush mechanisms that require more time to refill after every flush than other types of toilets. In addition to turbulence in the bowl itself, sound can also be produced by splashing or bubbling around the overflow pipe.

The noise made when toilets are flushed varies between individual bowls and even between different toilets of the same make and model. The sound of running water on its own is typically not a concern, however, a toilet that makes an unusual noise should be checked by a qualified plumber to check for possible defects.

5 Common Toilet Flushing Noises

The sounds that flushing toilets make are often a mystery to homeowners. Here’s what your toilet could be saying:

1. Foghorn Noise When Flushing Toilet

foghorn noise flushing toilet

A metal ballcock fill valve is a simple device that controls the flow of water into your toilet tank. In most toilet tanks, the water level is controlled by a float attached to a lever mechanism.

A ballcock fill valve works by sucking water from the tank into the toilet bowl to flush. And when you leave the bathroom, that water in the bowl must go back into the tank. The valve makes a humming or foghorn noise as it sucks the water up out of the toilet.

Trouble is, sometimes the sound doesn’t stop, especially if there’s some sort of blockage in the line. If this is your problem, you’ll hear a foghorn noise every time someone flushes your toilet.

If this happens to you, try backing off on how much toilet paper you use. Or get rid of your kitty litter box because that could be causing some clogs.

Another problem can occur if you are using a “flushable” bathroom cleaning product (such as a bleach tablet). These products can often form a hard plug in your toilet drain line that sends out a foghorn noise every time someone flushes. The best thing to do is have your plumbing line snaked and cleaned by a plumber.

2. Loud Vibrating Noise When Flushing Toilet

loud vibrating noise flushing toilet

The most common reasons for a toilet to make a loud vibrating noise when being flushed are either a loose chain or lift wire, or a flapper that is too tight.

The flapper is what forms the seal between the bowl and the tank when it is closed. It forms the watertight barrier that prevents any water from escaping from the tank.

The chain or lift wire is responsible for raising and lowering the flapper when you flush. When your toilet makes a loud vibrating noise, either the lift wire or chain has become loose due to wear and tear. This can be fixed by tightening them with a screwdriver and a pair of pliers (to bend them).

A flapper that is too tight can also cause this problem, so if your toilet is making this noise and your chain or lift wire is fine, try adjusting your flapper instead.

Moreover, a small wrench can be used on most toilets to turn the nut where the chain connects to tighten it slightly. After doing so, flush your toilet again. If it still makes a loud vibrating noise, you will need to replace the flapper altogether.

3. Groaning Noise When Flushing Toilet

groaning noise flushing toilet

Groaning noises in toilets are usually caused by a defective valve that controls the water refill. The most common causes of groaning noises are a leaky flapper or a worn-out fill valve in the toilet tank. If the noise occurs after you flush, suspect a worn-out fill valve or ballcock.

In many cases, replacing the fill valve cures the problem. But if you hear the groaning while flushing and the noise stops when you stop flushing, it’s probably a faulty flapper. Replace it by following these steps:

  • Turn off the water supply to the toilet at the shutoff valve under the toilet. Remove the lid from the toilet tank.
  • Locate and remove screws that hold down the flapper assembly and two screws that hold down the tank top.
  • Slide-out and replace faulty parts, then replace all parts and tighten screws.
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Do not overtighten or you may crack or break it. Reattach the lid and turn on the water supply to flush out air from the line, if necessary. Test for leaks around the base of the toilet bowl by placing several drops of food colouring in the tank near the rubber ring; if colour appears in the bowl without flushing, you leak.

4. Gurgling Noise When Flushing Toilet

A gurgling sound when you flush your toilet is a sign of a clogged pipe. The noise is caused by trapped air inside the pipes of the drainage system. A clog forms on the main drain line, causing air to become trapped.

The air pressure then pushes back against the water going through the plumbing pipes, creating negative pressure. This creates low-pitched noises that can range from a gurgle to a hiss.

If you’re hearing unpleasant sounds while you flush your toilet or while your sink drains, check for a clog. All it takes is one small clot to completely ruin a quiet bathroom!

There are two common causes for this problem: Hair and debris in the sink or commode and an external blockage in the main drain line, also known as the lateral drain line.

If you have hair and debris caught in your sinks or commode, you can try using a plunger to remove it. If that doesn’t work, try snaking out your drains with an auger or plumber’s snake.

However, if you have a clog in your main drain line, you’ll need to call a professional plumber to snake it out for you.

In addition, check to make sure that no water is trapped in any sections of pipe that are installed on an angle because this can also cause negative pressure and gurgling sounds.

5. Whooshing Noise When Flushing Toilet

A whooshing noise when flushing indicates that the toilet is unable to empty into the main drain. The noise is caused by air being sucked into the tank from the bowl, through the siphon tube, and then being blown out of the fill valve.

If you hear a whooshing noise, you can try flushing again to see if it clears itself. However, if it happens consistently, your toilet’s siphon tube may be clogged. This could be due to a build-up of mineral deposits.

You may also hear a whooshing noise when using a low-flush toilet designed for conservation purposes. These toilets use less water per flush to conserve water. However, they may require more than one flush to empty their tanks into the main drain.


Flushing noises are a part of our everyday life that we normally never pay attention to. However, they can turn from being simple sounds into real warning signals when we ignore them.

One sound like a rattling or a whistling from the tank should not be ignored. That sound indicates that your toilet is in trouble, and you should immediately give it some attention.

But, again, every sound on its own does not necessarily mean trouble for your toilet. You would have to consider all the other flushing sounds together with the appearance of water on the bowl surface for that conclusion.

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About the Author: AJ

AJ is a self-confessed soundproofing nut. He has written full-time on Quiet Living for the past 4 years, and has a wealth of knowledge about living a quieter life, soundproofing and fixing loud noises.

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