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Is Your Toilet Making Noise After Flushing? Here’s Why

Published: February 27, 2024
Toilet making noise after flushing

If your toilet runs when you’re not using it or makes hissing, bubbling, or loud noises, you might have a plumbing problem on your hands. There are three main sounds that indicate issues with your toilet, but they can be caused by a wide variety of things. Knowing the components of a toilet tank and what can cause a toilet to stop working properly can help you diagnose problems on your own and also know when it’s time to call a plumber if your toilet is making a strange noise.

Here are some common issues that can cause your toilet to make noise.

Watch Out for These Three Toilet Sounds

If your toilet makes these sounds when it’s running or after flushing, you likely have a float or clog problem. You may be able to fix float issues yourself, but persistent clogs require the expertise of a professional plumber.

Here are three toilet sounds to watch for.

Foghorn Noise

If your toilet makes a sound like a ship’s foghorn, it might be because of a loose washer inside the “float.” The float is a black, ballcock-style valve that is common on older toilets. To test if this is the case, lift the tank lid and flush your toilet while holding up the float. If the foghorn noise goes away, a loose washer is the problem. This issue can be easily fixed by taking apart the float and finding the loose valve, or you can contact a plumber to replace the component for you.

Hissing or Whining Sound

It’s normal to hear a bit of hissing as your toilet tank refills, but continuous hissing can be a sign that there’s a problem. The sound could be caused by a worn-out flap because when this part starts to break down with age, it can no longer create a seal. This allows water to go into the bowl, letting the tank refill continuously. Broken flaps can waste a lot of water, so you should replace this part or contact a plumber to do so right away.

A different type of float problem can also cause a hissing noise. The float may be rising higher than the overflow tube. If it is, use the clip on the side to move it down several inches so that the float is positioned on top of the overflow tube. This should stop continuous refilling and the hissing sound. If it doesn’t, contact a licensed plumber ASAP.

Gurgling or Bubbling Sound

toilet-making-noise Is Your Toilet Making Noise After Flushing? Here's Why

Gurgling or bubbling sounds in your toilet usually mean there is negative air pressure built up somewhere in the drain line, typically caused by a clog. When the pressure is released, it causes a gurgling or bubbling sound coming from your toilet bowl. To get rid of airlocks, you first have to get rid of the blockage. You can try to do this using a plunger or drain snake, but if it doesn’t work, contact a plumber. A gurgling sound can be caused by anything from toilet paper clogs to tree root obstructions, which can lead to backups in your sink or bathtub. 

toilet-making-noise Is Your Toilet Making Noise After Flushing? Here's Why
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Common Reasons Why Your Toilet Keeps Making Noise

Many plumbing issues can cause your toilet to make unusual noises, but if your toilet is making loud noises, you could be looking at a more serious problem.

Here are the most common reasons your toilet keeps making noise and what to do about them.

Your Fill Valve Is Broken

The fill valve in your toilet controls water flow into the tank after you flush. If your fill valve is worn out or faulty, it may cause a whining sound after flushing. You can easily check if the fill valve is damaged: just open the tank, find the valve, and check for leaks, cracks, or debris.

If you notice any issues, you can replace the fill valve according to the manufacturer’s instructions. There are universal fill valves, but it’s best to use one that’s specifically designed for your toilet. If you’re not comfortable doing this, it’s a good idea to contact a plumber.

Clogged Pipes & Drains

Clogged pipes and drains are some of the most common plumbing issues. A foul odor, drain and sink backups, and low water pressure are all signs that your plumbing system is clogged.

toilet-making-noise Is Your Toilet Making Noise After Flushing? Here's Why

Clogs and obstructions in your toilet pipes cause your toilet to make noise when flushing. Clogged pipes obstruct the flow of air and water in your toilet, which creates gurgling and bubbling sounds.

You can unclog your drains and pipes using a plunger or an auger, but if the issue persists, you should contact a professional plumber to diagnose the problem and address it properly.

Mack Washer Is Loose

The mack washer, also called the tank O-ring seal or tank-to-bowl, is a small rubber or plastic piece that seals the water inlet and prevents leaks. A damaged or worn-out washer leaks water into the tank, creating a hissing or whining sound. The sound happens when water flows through a narrow opening, creating vibrations in the toilet pipes.

A malfunctioning washer can cause a constant flow of water and a continuous hissing or whining sound. Replacing the washer is relatively simple, but you can always contact a plumber.

Low Water Pressure

Low water pressure causes a weak flush and traps air in the pipes. When the air is released, it can create a loud noise like a gurgling or whistling sound. On the other hand, high water pressure can cause pipe vibrations, creating a humming or whining sound.

Water pressure issues can also cause water hammers. This happens when water flows through a pipe and is suddenly stopped, causing it to slam into a valve or fixture and create a loud banging sound. If water hammers are not addressed, they can seriously damage your plumbing. You can install a hammer arrestor, but it’s wise to call in a plumber to find the root of the issue.

Damaged Ballcock Assembly

toilet-making-noise Is Your Toilet Making Noise After Flushing? Here's Why

The ballcock assembly, which is a float, an arm, and a valve, controls the water level in the tank by shutting off the water supply when the tank is full. Setting the assembly too high can prevent the valve from closing correctly, allowing water to flow into the rank and resulting in continuous hissing. If it’s set too low, the valve closes too early, leading to a weak flush and creating air bubbles in the pipes, which make a gurgling sound.

A damaged or worn-out ballcock assembly can cause sounds from hissing to whistling to humming. To replace a faulty ballcock assembly, turn off the water supply, remove the old assembly, and install a new one.

Toilet Vents Are Blocked

A toilet vent is a pipe that extends from the toilet bowl to the roof, allowing air to flow into the drain system.

When you flush the toilet, water rushes into the pipes and creates a vacuum, pulling air through the toilet’s trap and into the bowl. Air is released through the vent, creating a whooshing sound. If debris, insects, animal nests, or anything else blocks the vent, your toilet may gurgle or whine when flushed.

A blocked or clogged vent traps air, which builds up when you flush and creates a loud gurgling or whistling sound. It can also cause water to drain slowly or lead to a toilet overflow.

Flapper Valve Is Damaged

A flapper valve is a rubber or plastic seal that covers the flush valve and releases water into the toilet bowl when you flush. A damaged or worn-out flapper valve won’t seal properly, allowing water to leak from the tank into the bowl. This causes the toilet to run continuously, creating a hissing or whistling sound.

A worn flapper valve can also cause water to drain slowly from the tank, resulting in weak flushes, air bubbles in the pipes, and gurgling or whistling noises. Misaligned flapper valves can allow water to flow continuously into the bowl, creating a loud, constant noise. 

toilet-making-noise Is Your Toilet Making Noise After Flushing? Here's Why

Choose LimRic Plumbing, Heating & Air for Toilet Solutions in Charleston, SC

When you need toilet repair and other plumbing services in areas of South Carolina like Charleston, Summerville, Mount Pleasant, and the surrounding region, turn to the licensed plumbers at LimRic. We can handle everything from leaky seals and faulty flush mechanisms to clogged toilets.
If you experience an urgent issue like a sewer backup, we also provide 24-hour emergency plumbing services for fast, professional solutions that minimize mess and stress. If you notice your toilet making noise, don’t hesitate to get in contact with our team of licensed plumbers.

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