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While it’s pretty normal for a toilet to make a noise when flushing, if it makes anything different to this flushing noise then it’s time to get investigating. As a soundproofing expert, I get asked quite often what to do if a toilet is making noise. I decided to write an article to help others in this situation.
The first thing to do if your toilet is making noise is to determine the source. Providing nothing is leaking or broken, your next step would be to soundproof it using a range of fairly standard soundproofing materials. Where you apply these will of course depend on the source of the noise.
In this article, I’ll look at the most common sources of unusual noise from a toilet, along with some easy fixes to make it quieter. Just remember, though, that this isn’t a plumbing article, so if you encounter a problem you can’t fix then don’t hesitate to call in a plumber.
Sources of noise in toilets
The flushing noise a toilet makes is perfectly normal, but there are ways to soundproof against it. However, more pressing issues involve things like hissing pipes and foghorn noises, which can be fairly easy to remedy.
As I mentioned, the first step in soundproofing a noisy toilet is to determine the source of the noise. Providing it’s not too big an issue, you should be fine to fix it yourself. However, issues such as clogged pipes or leaks are best identified and fixed by a professional plumber.
So, before we move on to solutions, let’s take a look at some of the more common sources of noise from a toilet. Hopefully, these should help you identify your issue, which will then lead you to the best solution.
Toilet making a foghorn sound
One of the more common issues (particularly in older toilets) is a foghorn sound that happens when you flush. While this noise isn’t the worst thing in the world, it can be irritating, particularly if you need to flush in the night and risk waking people up.
The first reason could be that your toilet has an old metal ballcock fill valve fitted inside the cistern. The noise is most likely caused by a loose washer, which causes parts to rattle, or in turn could have affected the seal, which impacts pressure.
Another related reason is again found in old toilets. Many old toilets were designed to run off a gravity system rather than a mains water supply, with the former working at much lower pressure.
Simply put, a foghorn noise when flushing is most likely caused by a pressure issue within the cistern. That’s why it makes a noise when flushed: the water pressure is too high (or low), resulting in air in the system.
Luckily this issue is fairly easy and inexpensive to solve and simply involves replacing the fill valve for a new one. It’s best to get a high-pressure valve, particularly if you’re running off the mains water.
Toilet is making a hissing noise
Another fairly common toilet issue is a hissing noise when it’s flushed. Much like the foghorn noise, it’s triggered by flushing but can continue for a while after, making it a common irritant in many households.
This is another problem caused by the fill valve but isn’t directly a pressure issue. Over time, particularly in hard water areas, the valve can become clogged by mineral deposits. However, the issue can happen in other areas if there’s a higher than normal amount of sediment in the water.
Effectively, this causes the cistern to fill up more slowly, which in turn increases pressure in the pipes. This is where the hissing sound actually comes from, but it’s particularly noticeable in the toilet because this is where the pipe ends.
Luckily this issue shouldn’t cause any damage to the toilet, even if left unchecked for a long time. However, it will make it fill up very slowly, and the noise itself is usually annoying enough to make you want to fix the issue.
The problem is relatively simple to solve; you’ll need to either clean the inlet valve or replace it completely. I’d generally recommend replacing it completely, as it’s not an expensive piece of kit and it’ll ensure you won’t have the problem again for a while. Check out this video for more information.
Toilet is making a hammering noise
Your toilet making a hammering noise is one of the more rare problems and is definitely one that needs fixing quickly. Unlike the other issues listed so far, this can cause damage to both your toilet and pipes, so it should be dealt with.
The hammering noise can either be a single bang after flushing or a repeated jackhammer type noise, which indicate different problems. A single bang is likely caused by a worn or damaged washer in the shut-off valve, which is connected to the inlet pipe in the wall.
A repeated banging noise is most likely caused by an obstruction in the pipe, rather than damage to the valve. The most common obstructions include rust or mineral or sediment build-up.
To troubleshoot water resonance issues, try the following:
- Turn off the water supply to the property at the mains. This valve could either be located inside the property (under a sink) or off the property (in the street).
- Next, run all the cold water taps, starting with the highest (upstairs) and moving to the lowest (downstairs/basement).
- Flush all the toilets and leave the open faucets to drain for around 30 minutes.
- Turn the water supply back on and wait about 10 minutes for the taps to flow properly.
- Turn all the taps off, starting at the bottom and working backward to the top.
- Give it another 10 minutes and then try the toilet again. Hopefully this should have fixed the issue.
If this doesn’t work then the next solution is to replace the shut off valve. This is a bit more complicated but should fix the issue. Before then, it might be worth trying to clean out the system, as explained in this video.
This is a fairly self-explanatory name for a fairly simple problem. Ghost flushing is when a toilet seems to flush on its own without anyone being in there. Rather than it being a ghost, it’s most likely caused by a leak in the cistern.
A leak into the toilet from the cistern causes a constant supply of water to flow out. Once the water level gets low enough, the float activates the filling mechanism, causing a flush.
The most common causes of ghost flushing are worn or loose parts inside the cistern. It could be caused by the toilet flapper, a loose-fill tube, or issues with the float ball. While these issues aren’t the most difficult to solve, troubleshooting can be problematic, so it might be best to call in a plumber.
To determine if you have a leak, simply put some food dye into the cistern. Leave the toilet unflushed for half an hour, and if there’s any trace of blue water in the toilet bowl, you have a leak. However, this narrows it down to one of 4 or 5 issues, hence why a plumber is recommended.
How to deal with a toilet making noise
Now that we’ve looked into the most common toilet noises, it’s time to look at some solutions. Earlier in the article I mentioned some plumbing fixes, and while I’ll explain these in a bit more detail here, I’ll also focus on some soundproofing solutions for fixing things like loud pipes.
1. Give the toilet system a good clean
As you can see, several of the issues are caused by debris or blockages in the inlet system. Many of these can be fixed by giving it a deep clean, which should hopefully remove any build-up.
To clean out the cistern, try the following:
- Turn off the water supply to the toilet. This should be a small valve on a pipe just behind the toilet, but might be located elsewhere in the bathroom.
- Flush the toilet and take the lid off the cistern.
- Lift up the float cup inside the cistern and hold it in its up-most position.
- Turn the valve cap and arm counterclockwise to unlock. This should now lift easily off the body of the valve.
- Check the cap for debris around the seal, which is the little rubber disc. Also, check the valve body that’s still in the cistern for debris.
- Put a cup over the valve opening in the cistern and turn the water supply back on for 10 seconds. The cup is to stop the water spraying everywhere, but the pressure should dislodge any remaining debris.
- Return the valve cap to its original place and put everything back together.
- Put the cistern lid back on and turn the water on, which will cause the tank to refill.
This should effectively clear out any debris in the inlet system, which will hopefully stop a number of hissing noises. If this doesn’t solve the problem then consider replacing the valve instead.
2. Seal off the water tank
The actual act of the toilet cistern refilling with water can be surprisingly noisy, and anyone with any knowledge of soundproofing will know that even the smallest gap can leak plenty of noise.
My recommended solution for this is to soundproof the tank by sealing the gap between the cistern and its lid. The easiest way to do this is with weather stripping, which you should apply where the lid rim sits on the tank.
Luckily weather stripping is inexpensive and readily available. It’s a surprisingly useful material in soundproofing, and while it was designed to block out draughts, it’s equally effective at soundproofing.
The objective here is to make the gap between the lid and the tank as small as possible. If that doesn’t solve the problem to the degree you’d like, then consider wrapping the tank in some kind of soundproof material, but bear in mind this might not look amazing.
3. Wrap the pipes to reduce noise
While pipe hammering can be caused by valve issues, another likely cause is the pipe not being secured properly to the wall. This can be remedied with a few new screws to hold it in place, but it’s worth soundproofing the pipe properly too.
Some people don’t enjoy the sound of the pipes refilling, particularly if they live in an apartment block or don’t want to wake others in the night. This is when soundproofing the pipes is the best solution.
The best material to use here is something heavy and designed for soundproofing, such as mass loaded vinyl (Amazon).
. This is one of the best materials in the soundproofing world because it’s limp mass. In short, limp mass doesn’t vibrate when it comes into contact with sound waves, making it perfect for this.
Wrapping the pipes in mass loaded vinyl will dampen any noises they make. However, this job could either be really easy or really complicated depending on what your plumbing is like.
If your pipes are exposed enough, it should be a simple fix. If the pipes are located in the wall, though, you’ll need to take that down to reach them. This might be too much work for some, but if you’re willing to try it then you’ll have much better results.
4. Fill in cavities around the pipes
If you’ve decided to get into the DIY and are taking the wall down to access the pipes, now would be the best time to add some more soundproofing solutions to the space. The more you fill it up the less noise it’ll make.
Much the same as you’d fill a wall cavity when soundproofing a room; you should do the same here. Filling in the wall cavity will dampen any sound waves, which can resonate and amplify in an open yet enclosed space like a wall cavity.
The best thing you can use here is acoustic cavity insulation, such as Rockwool (Amazon). This stuff is specifically designed to add dense mass to a space, which massively reduces sound resonance. Adding as much of this as possible round the pipes will make a big difference.
Similarly, while you’re in the wall, fill any gaps with acoustic caulk. This will help with the overall soundproofing project, as even the smallest gap can leak noise. If you’re confident that it’s the pipes making noise, this will be your best solution to the problem.
5. Soundproof the actual room
Another – possibly more practical – option to soundproofing just the toilet is soundproofing the entire bathroom. However, I’d still ensure that there are no problems with the toilet itself before you go down this route.
As discussed, if your toilet is making a noise this can often signal a bigger issue. However, if it’s something simple like a loud flush, the seat banging, or just general bathroom noises, then soundproofing the space might make more sense.
This can be beneficial for a number of reasons. For example, most people don’t appreciate the idea of being heard while using the toilet, and having a soundproof bathroom can be useful if you don’t want to wake others while getting ready for work.
Soundproofing a bathroom isn’t much different from soundproofing any other room in the house, except that any wall finishing will most likely need to be waterproof. This isn’t a massive issue, but you’ll need to be good at DIY to do it properly.
I’d recommend starting with the bathroom door, as these are usually hollow and so let out a lot of noise. The simplest solution is to buy a solid core door (Amazon), as this will solve the problem with the least amount of effort.
However, if this is outside your budget, then try reinforcing the door with some acoustic drywall on either side. Cut it to the right size and then line everything with acoustic caulk.
After that, the next steps should be adding mass to the walls if possible. This should involve filling cavities with insulation and adding another layer of drywall if you can. If your bathroom is tiled then this could be a problem, and it might be worth getting a contractor in to help.
Finally, adding some underlay to the floor will make a difference, particularly to hard floor surfaces like tiles. You can buy soundproof floor underlay (Amazon), and this is what I’d recommend here.
Check out my review of the underlay I recommend.
Soundproofing the floor will minimize resonance of footsteps, which will mostly be for the benefit of people below you.
Some final thoughts
As you can see, there are several solutions for what to do if your toilet is making noise. I recommend troubleshooting the problem before you try drowning it out, just to ensure it’s not a sign of bigger issues. However, if you’re content that it’s just a noisy toilet then treat this like any other soundproofing project, and plan properly in advance.