Why is My Toilet Whistling After Flushing and How To Fix It

When you hear a whistling sound from your toilet there is a cause for alarm. It means that there is an issue you need to fix by replacing damaged parts in the toilet bowl. The obvious culprit in this case is a damaged fill valve. Sometimes the whistle might be low and indiscernible, and other times it can be too loud to ignore. When the noise becomes too loud is when you should be concerned. At this stage, it will be clear that something is faulty with the toilet. Luckily fixing the toilet whistling problem is simple, inexpensive, and you may not need to call a professional plumber. Read on to learn why your toilet whistles and what you can do to fix this problem.

White toilet with white cabinet above it.

Reasons why your toilet could be whistling

Your toilet could be whistling because of several reasons;

  1. 1. A leaking Valve 
  2. Damaged fill Valves
  3. Calcium deposits building up inside the pipes

If the fill valve is damaged or if there is wear and tear inside the gasket, you are likely to hear a whistling sound coming out of your toilet. After flushing, the faulty valve causes a vibration within the tank. This vibration results in a hissing/whistling sound.

How to stop the toilet from whistling

Fixing the whistling toilet should not be too challenging. If you have an old metal ballcock valve toilet, you can replace the gasket to stop the whistling. The newer -model fill valves are made from plastic and are inexpensive compared to the metal ballcock valves. The steps below shows you how to fix this problem without needing to call a plumber;

Check the Water Supply Valve

The water supply valve regulates the level of water inside your toilet bowl. This valve is usually found at the back of the toilet, attached to the wall. It is unlikely that the whistling problem comes from here but it is good to check all possible problematic areas. Maybe someone may have tampered with this valve resulting in the disturbance of the water’s flow inside the toilet bowl. 

Close up of toilet valve behind the toilet bowl.

Check the Fill Valve

Once you ascertain that the whistling sound is not coming from the water supply valve, check thefill valve. Check to see if there is any debris lodged here that may be interfering with the water flow and remove them. Wipe the surface using a piece of clothing and then rinse with clean water. Flush the toilet to see if the problem is fixed. If not, go to the next step- replacing the fill valve.

How a toilet fill valve works

Before you learn how to replace the fill valve, you should understand how it works. After flushing the toilet, the water level goes down. The fill valve will rise or fall as the water level changes. Once the toilet bowl is full, the valve closes to prevent more water from flowing into the bowl. If the valve is damaged or defective whistling sounds will come out of your toilet. The louder the whistling sound is, the closer your toilet is to failing. If water entering the bowl is not regulated, you risk having an overflow.

Replace the Fill Valve

Time needed: 20 minutes

To replace the fill valve inside your toilet follow these steps:

  1. Locate the water supply valve

    It should be under the toilet tank. Turn the knob and shut the water off. The repair process will be easier if there is no water flowing into the bowl.

  2. Remove water

    Empty the remaining water inside the tank. Flush the toilet and then use an old cup to remove water still in the bowl. If there is a small amount that you can’t get out, use a towel or sponge to soak it up.

  3. Unscrew the nut

    There is a plastic nut from the old valve at the bottom of the toilet tank. Find the nut and unscrew it.

  4. Place the new valve

    Place the new valve and ensure the washers have been placed correctly. Adjust the new fill valve to fill the right water level needed and then attach it correctly to the toilet tank.

  5. Flush

    Flush and listen closely to see if the whistling noise has disappeared.

If the gasket is damaged, you need to replace it. If you are already familiar with the workings of a toilet, it would be easier to replace the entire valve. Opening the valve to find the gasket may not be a straightforward affair for most people. 

Call a plumber

Whenever you are in doubt about your capability to fix the toilet you can always call a professional. Find someone close to your region who is available whenever you need them to fix issues in your bathroom.


What happens if I ignore the toilet whistling problem?

I would not advise that you ignore this whistling issue. The shrieking of the toilet is annoying enough. Imagine how unsettling this can be when happening in the middle of the night when you want to sleep. Replacing the fill valve is not a hard task and it is not expensive. If the valve is not replaced on time, the toilet will use more water than necessary and this could mean you accumulate more water and electricity bills. A damaged fill valve can result in wastage of hundreds (or thousands) of gallons of water.

How much does replacing a fill valve cost?

On average, a fill valve is not expensive but it all depends on where you buy it from. Many modern toilet valves are made from inexpensive plastic materials you can pick up cheaply from any mall. If you decide to use a professional plumber to fix it for you, it may cost you more depending on where you reside. 

Will a gurgling toilet fix itself eventually?

It is possible the gurgling sounds go away on their own if the drain clog clears itself. If the issue lies in your main sewer line, you’ll need the help of professional plumbers.

What is ghost flushing?

Ghost flushing, also known as phantom flushing, occurs when the toilet tank flapper is no longer creating a watertight seal with the flush valve, causing water to unnecessarily leak into the toilet bowl.


Loud noises coming from your toilet should concern you because they mean that there is something wrong with your toilet. The last thing you want is to have your bathroom flooded because of a faulty toilet. It should be easy enough to fix a whistling toilet by fixing the fill valve. If not, you can always hire a professional plumber to replace the valve and take care of the nasty and irritating noises coming from your toilet sink.

Adrienne Carrie Hubbard
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