Why Does The Toilet Make a Whistling Noise (Fix It Now!)

Noises coming from your toilet can be irritating to deal with as a homeowner. They can interrupt your daily activities and cause unnecessary worry. 

Even worse, unusual sounds can signal expensive and involved repairs in the near future. If your toilet whistles after use, you may be wondering what the problem is and how you can fix it as soon as possible. 

Toilets make a whistling sound when there’s a problem with the fill valve or gasket on the fill valve. Whether the parts are worn down due to age or there’s a crack, they have to work extra hard between flushes, causing a high-pitched squeaking noise. To fix it, you can attempt a DIY replacement or call a professional. 

So, what exactly is a fill valve and a gasket, and how can you use this information to fix that annoying whistling sound in the bathroom? In this article, we will break down everything you need to know about what’s causing your toilet to whistle and how to get rid of the nuisance once and for all. 

What is that whistling sound?

A whistling sound coming from your toilet can be puzzling. There is one common cause for these noises, but they usually occur in the same instances: either during or after use. 

A whistle from the toilet during or after use

While using the toilet, you may hear a loud or high-pitched whistling noise. You may notice this is triggered each time you flush. 

In other scenarios, this reaction may be delayed. After using the toilet, you could go to the other room and hear screeching and whistling from the bathroom while doing another task. 

A whistle is an unusual sound coming from a toilet. When you notice these strange noises, it’s definitely a sign of a problem that should be addressed sooner rather than later. 

Main cause of a whistling sound from a toilet

The main cause of a whistling sound from a toilet is a broken or malfunctioning fill valve. If you notice strange and high-pitched noises during or after use of your toilet, there’s a good chance your fill valve needs to be repaired or replaced to get rid of it. 

Job of a fill valve

The fill valve is located at the top of the toilet inside the tank. Its job is to let water in and out of the toilet before and after a flush. 

Immediately after flushing, the fill valve replenishes the tank with more water. The valve opens the supply pipe automatically when water levels reach a certain threshold. 

Fill Valve
Fill Valve

Without the fill valve, your toilet wouldn’t be able to flush out waste effectively. There would be no water to push it through the pipes as intended. This is why it’s so essential for this component to remain in good working condition, and any problems can be concerning. 

Broken fill valve

When the fill valve is broken, it can no longer effectively refill the tank after each flush. Excessive wear on this part can cause too much water to collect inside the tank instead with no control. 

Since the water runs almost constantly with a broken fill valve, you can expect to hear some strange noises, like whistling, coming from the bathroom after you flush. 

Cracked gaskets on fill valve

A gasket is a wax ring located on the bottom of the toilet tank near the fill valve. It connects the toilet to the plumbing system in the ground below it. 

The gaskets on the fill valve can also contribute to high-pitched noises. When worn down or cracked, they can shake when attempting to refill the toilet tank. These vibrations make the toilet whistle either during or shortly after flushing. 

To check and clean your gaskets, turn off the water supply connected to your toilet and flush out any remaining water. Open the lid on your toilet tank and unscrew the bolts to remove it. 

Cracked gaskets

Pick up the toilet tank with both hands and flip it over on its side. When it’s upside down, you will notice an opening in the center with a ring made of rubber (the gasket). 

Check it for any cracks or visible damage. If you need to replace the gasket, simply remove the old one with your hand and pop another one into its place. Cleaning the gasket is just as simple; use a towel or brush and gentle cleaning solution to scrub any residue. 

How to fix a fill valve on a toilet

When you notice a problem with your fill valve, you will need to repair it to get rid of that annoying whistling sound. A poor fill valve can also cause the toilet to not flush completely. Understanding the cause of the issue is only half of the battle. 

You can always call a professional to help you out with this process, but if you’d prefer a DIY solution, try the following steps to fix your fill valve. 

Turn off water supply

Before completing any kind of repair on your toilet, you will need to turn off the water supply. This switch can be found in the back of your toilet. 

Water Supply Switch

Drain water from tank

After turning off the water supply, flush the toilet one last time. This will expel any remaining water into the drain, leaving you with a completely empty tank. 

You can also use a sponge to soak up any additional water left behind before proceeding. When the tank is dry, you will be ready to begin the repair. 

Draining switch on tank

Remove the old fill valve

To remove the old fill valve, open the toilet tank and locate the plastic cap at the top of the existing valve. Loosen it by turning it counter-clockwise with your hand. 

Next, slide the float cup upward to the top of the fill valve. This is a large, cylinder-shaped component also made of plastic. Turn the cap one more time while applying downward pressure and remove it from the tank. 

old fill valve

After that, place an upside-down cup in the cap’s position. Turn the shutoff valve slightly to allow water flow while you’re holding the cup in place with the other hand. 

Replace with a new valve

Once all of the excess build up and any debris has left, turn off the water supply one more time and proceed to remove the old seal on the fill valve. You will notice a metal needle inside the cap you removed from the old valve. This is where the new piece will be installed. 

Replacing new valve

Insert your new valve into the same position. Make sure the orientation matches the seal you removed exactly, otherwise it will not work properly. 

Set new valve to correct position

When installing your new valve, it’s essential to set it to the correct position. Otherwise, the components will not be able to work together efficiently, and you can be dealing with more toilet repair issues in the near future. 

Take care to set the new valve near the middle. Avoid pushing it to the bottom of the tank for peak functionality and minimal issues moving forward. 

Turn water back on

After successfully replacing your fill valve and ensuring it’s positioned properly, you will need to turn the water back on to resume use of your toilet. First, place the lid back on top of your toilet tank. 

Return to the shutoff valve located in the back of your toilet. Turn it back on by turning it in the other direction. Before you finish up the repair, be sure to flush the toilet again. This will ensure everything is working properly before you move on and consider the task complete. 

At this point, you have (hopefully) fixed the annoying sound coming from your toilet. You should not hear any whistling, squeaking, or high-pitched noises after you flush. 

Pay close attention to any sounds coming from the bathroom for some time after you leave the room. If you still hear nothing, your problem is fixed! However, if there’s still a noise or anything unusual, you may need to consult with a professional. 

Call a plumber

If you’ve tried the troubleshooting steps outlined above with no results, it may be time to call a plumber. There are other instances where you shouldn’t attempt a DIY solution at all. Read on to learn when you should seek professional help and what to expect when doing so. 

When to call the plumber

You should call a plumber when you’ve replaced the fill valve on your own but you’re still hearing noises. This can be the exact same whistling sound you heard before, or something else unusual. 

If your toilet continues to make noises even after you’ve tried to fix it, there could be a bigger problem. After doing everything in your power to complete the repairs, it’s best to leave it to an experienced professional from here. They can inspect your unit to determine the exact problem and come up with a permanent solution. 

Similarly, don’t hesitate to call a plumber as the first step if you’re not confident in your DIY skills. There’s no shame in seeking professional help right away if you need it. 

Cost of repair and labor

When you call a professional to help you with your toilet repair, you can expect them to charge on an hourly basis. The average hourly cost for a plumber falls between $75 and $200. 

Depending on the professional you choose, they may have a fixed rate pricing structure or a fee minimum. The average cost of a fill valve repair is $150, however you should reach out to a plumber in your area for an exact pricing quote. 

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