Toilet Making Noise When Not in Use-Causes and Fixes

A toilet making noise when not in use can be annoying and, at times, embarrassing. You might also start to wonder if there is something wrong with it. Understanding the cause of the noise can help you find a solution and know when you need professional assistance.

The most common reasons a toilet makes noise when not in use are leaky flap valves, malfunctioning flush tank fill valves, or calcium deposits inside the plumbing. In most cases, replacing the faulty parts or cleaning the pipes should stop the noise.

If your toilet is making gurgling, banging, or hissing sounds and you want to find out how to fix them, keep reading!

Why Does My Toilet Keeps Making Noise Even When I am Not Using it?

If your toilet is making noises even when not in use, it might indicate a faulty or worn-out valve system in your flush tank or, in some cases, the deposition of minerals inside the pipes supplying water to the flush tank.

Here are some of the reasons why your toilet seems to turn into a sound machine suddenly-

High-pitched squealing or hissing noises

It is normal to hear a brief hiss coming from your flush tank as it refills after you activate the flush. However, if the hissing continues or the sound is more of a high-pitched squeal, it might indicate a problem with the flapper.  

A flapper is a small valve that controls water flow from your flush tank into the toilet bowl. Once you activate this valve, all the water in the flush tank rushes into the bowl. Once all the water is emptied, the flapper snaps back in place, allowing the flush tank to refill.

a person holding a defective flapper and a new one for replacement due to a hissing noise
Image from Honest Lee Handyman Services

If there is a problem with your flapper, it might not be able to close properly, forming a tight seal. It results in water escaping into the toilet continuously, making a hissing sound even when the flush tank is filled.

You can also experience a ghost flush if the leaked water is enough to activate the siphon of the toilet bowl. 

How to fix the hissing noise?

As the hissing noise is due to a faulty flapper, you will need to replace this part to eliminate the sound. While it is easy to replace the flapper, you will need a few tools and some plumbing knowledge. If you are not sure that you can fix the issue, you can always call a professional plumber to help you out.

Gurgling noises

If you hear a gurgling noise when your toilet is not in use, it might indicate a problem with your sewer system. A toilet makes gurgling noises when there is a blockage in your sewer system. The block might be somewhere in your bathroom, a sewer drains, or a vent stack.

A schematic section-view illustration of a contemporary Sanitary Sewer System depicting a residential connection to a public sanitary structure with text descriptions of the process.

It might be difficult to pinpoint the blockage without diagnosing the entire drainage system.

How to fix the gurgling noises?

If your toilet is making a gurgling noise, it is time to hand it over to professionals. Only trained plumbers can accurately diagnose and rectify the blockage. Trying to do it yourself might cause the problem to worsen.

Vibrating noises

If your toilet is vibrating noises soon after you actuate the flush, it might indicate a problem with the fill valve. When the diaphragm gasket in the flush tank fill valve is worn out or hardens, you might start hearing these vibrating noises.

You can easily diagnose this issue by lifting the lid of the flush tank and gently lifting the float arm connected to the fill valve. You might need to replace the intake valve if this stops the vibrating sound.

a man repairing a faulty fill valve in a flush tank
Image from Henry Plumbing Co., Inc.

How to fix vibrating noise?

A vibrating noise coming from a toilet is rather easy to fix. You need to replace the existing flush intake valve with a new one. Just remember to purchase a valve that is compatible with your system. Most intake valve replacements don’t require any special equipment either. If your toolbox has tools like a spanner and pliers, you should be able to get it done in no time.  

Noises due to calcium deposits in pipes

Calcium deposits inside the pipes carrying water can also cause your toilet to make noises as they can gradually block water flow. Unfortunately, it is impossible to predict whether calcium deposits are inside the pipes. You will need to unscrew the lines from the fittings and inspect them visually.

Calling a plumber to check for calcium deposits in your plumbing system is best.

calcium deposit in a pipe
Image from PLUMCORE INC.

How are calcium deposits cleaned?

Plumbers use either of the following three methods to clean the calcium deposits from the inside of your pipes-

  • Steam: Plumbers use a steamer to send high-pressure steam down the pipes to remove calcium deposits. The steam’s heat and kinetic energy help to loosen the deposits and break them off. 
  • Water: Jets of high-pressured water can also do the trick in some situations. When the plumbers send a jet of high-pressure water through the pipes, the calcium deposits can break off, cleaning the lines.
  • Industrial cleaners: In some cases, running professional cleaners through your pipes can help break down the calcium deposits. Most used chemical cleaners contain phosphoric acid, glycine, and barium nitrate.

Banging noises due to the water hammer

One of the most common noises from an idle toilet is banging sounds, also called water knocks. The noise occurs when the water crashes into itself due to the sudden closing of the flush valve. The knocking sound is usually heard just after your flush your toilet.

As the water comes into the flush tank with force, a sudden closure of the intake valve causes the water to dissipate all the kinetic energy it has in the form of sound energy, hence the loud sound.

newly installed water hammer arrestor in plumbing
Image from Manzon Development

Most modern plumbing systems have ‘hammer arrestors’ devices to prevent the water hammer. The arrestors have a chamber of air and a piston that acts as a shock absorber when the intake valve closes suddenly.

How to fix banging noises?

  • Check if your plumbing system has hammer arrestors and whether they are working properly.
  • If there is a problem with hammer arrestors, replace them immediately. If you have some plumbing knowledge, you should have no problem replacing them. Call the plumber if you are unsure how to get the job done.

Frequently Asked Questions

Are all noises coming from an idle toilet indicate a problem?

Unfortunately, yes! Your toilet is not supposed to make any noise if it is not in use. So, if you hear banging, hissing, or sloshing noises, your toilet is not functioning as it is supposed to and requires maintenance.

Should I call a plumber if my toilet makes noises when not in use?

Your toilet can make noises when idle due to several reasons. If the cause is a leaky flapper or a faulty intake valve, you can probably fix it. However, if you can’t diagnose the issue or are unsure about your plumbing skills, it is better to call a plumber rather than risk more damage.

To conclude

There are several reasons for your toilet making noises when not in use. While some of them can have an easy fix, others might need professionals to rectify. It is best not to ignore these noises and get your toilet back in order as soon as possible.

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