You may think water on the floor around the base of your toilet is not a big issue, even though the truth is – it can turn your bathroom into an indoor swimming pool in seconds! This type of leak is not naive, but how to deal with the leak when flushing toilet?
In this article, we will guide you through identifying the cause of the leak and then suggest solutions for different causes.
Sometimes the cause of the toilet tee bolts, other times it is the cracked toilet tank.
Seeing a leak when flushing toilet is indeed not a good sign.
We suppose you want a reliable toilet, and if so – here is how do you fix a leak like this and prevent more severe water damage in your bathroom.
Detecting the Problem
Toilets usually last for about 40 years and don’t require special care. 
People often don’t even realize that toilets can break, but leak when flushing toilet proves otherwise.
The wet bathroom floor is no joke, in more ways than one.
Not only you can slip and fall, but this also indicates a very serious problem – either with your plumbing or with the toilet bowl.
You should never ignore a problem such as this one.
It’s always better to act on time, as a leak when flushing toilet can turn into a much more serious matter if left unattended.
A Quick Tip
Don’t flush water from your toilet during the inspection, or right before it, even if you want to check where’s the leak coming from.
Larger amounts of leaking water from your toilet will only cause unpleasant odors in your bathroom. 
Further, standing water can cause structural damage to your entire property.
What is even worse, if your affected bathroom is on the second floor, the water will probably leak through the first-floor ceiling as well.
You should always inspect the entire toilet, including the bowl itself, the inside of the tank, and the water supply valve.
Sometimes, it’s enough to simply tighten nuts and bolts, but this isn’t always the case.
On rare occasions, you may even have to replace the entire bowl.
If you don’t have the required tools, or you aren’t certain in your handiness skills, it’s better to call the plumber.
Don’t risk causing a bigger issue than it already is.
Some simple mistakes, such as failing to notice some serious problem such as cracks in the tank, can cause a lot of damage.
The same goes for overtightening the bolts.
Don’t cause yourself more headaches than you already have and contact a plumber.
However, if you feel like you can handle this by yourself, you’re in the right spot!
Whether you have some plumbing experience or not, everyone can complete some easy fixes.
If you’re having a leak when flushing toilet, there are a few common reasons behind it.
- Loose fill valve or supply valve
- The nuts and bolts that are connecting the tank to the rest of the toilet bowl aren’t tightened enough.
- There is a crack on your toilet bowl
- The flapper isn’t working properly, so it’s not shutting down the valve seat, causing the water to leak into the bowl
- You have a toilet bowl not installed properly
Also, it’s important to thoroughly inspect the location of the leak.
The leak can happen at several places of the toilet bowl, including:
- At the base of the toilet
- Top of the tank
- Pipe under toilet leaking
- Leak between tank and bowl
The location of the leak can help you determine what’s causing the leak.
If you don’t know where to start, try looking for any hairline cracks that might appear on the toilet bowl.
Sometimes, you might have a cracked toilet bowl without even realizing it.
These cracks are small and easy to miss.
Other times, you might simply have to tighten a bolt.
Grab a wrench and check out to see if everything is in its place.
If nothing of this works, you should go on and check the gasket, flapper, or water supply line.
We’ll address everything in more detail in just a minute.
Sometimes, if your toilet isn’t installed properly, or if you have a toilet rough in dimensions, this might cause the leak.
If this is the case, nothing else will work but replacing the toilet bowl altogether.
Anything else can likely be repaired.
However, before you begin fixing a leak when flushing toilet, there are a few precautionary measures you should take.
First off, always wear rubber gloves.
Wastewater is dirty and you never know how your skin will react to it.
Not to mention how nasty it is!
You should also have a bucket and an old towel or piece of cloth nearby, in case any more water starts running from the toilet.
It would be best to turn the water supply entirely when dealing with any leaking toilet pipe, or any other plumbing.
Ensure the water is drained from the toilet before you begin.
How to Fix a Leak when Flushing Toilet?
Once you have found what’s causing a leak when flushing toilet, it’s time to try to fix the issue.
Keep in mind that various issues might require different fixes.
Here are some of them.
What to Do When the Flapper Is the Problem
You’ll know the problem is in your flapper if your toilet flushes twice.
It can also cause a toilet leaking from top of tank when flushed.
If you’re still unsure if the flapper is the issue, squeeze several drops of food coloring inside the toilet tank.
In case that after a few minutes the coloring leaks into the toilet bowl but you never flushed, then this is the issue.
Assuming you’ve already shut off the water valve, remove the toilet tank, and examine the flapper.
The flapper is that part of the toilet in the tank that lifts once you flush.
If the rubber on it is hard and not pliable, you should find a good replacement online or at the hardware store.
To replace it, just snap it off to remove it from the flush handle chain.
Then, simply pop the replacement flapper into its place and attach it back to the chain.
Turn the water on and try flushing to see if everything works properly.
If it works, but the water is still leaking, then something else is causing this issue.
What to Do When the Gasket Is the Problem
If you suspect the gasket is the culprit, the first thing you should do is disconnect the toilet tank from the toilet.
A good sign that this might be causing it is toilet leaks when flushed at base of the tank.
Keep in mind that the toilet tank is heavy and you will need someone to help you.
To remove the toilet tank safely, you’ll need to:
- Shut down the water valve and ensure the tank is empty
- Loosen the nuts that are located on the hold-down bolts using both a screwdriver and a wrench
- Loosen the jamb nut
- Release the tank from the bowl
Once you’ve done this, you should look at your gasket and see if it’s cracked or dried out.
If it is, you’ll need to remove the old gasket.
This isn’t difficult to do.
You should be able to simply pop the gasket off.
Then, you should easily just replace it with a new gasket.
Once you’re done, place the tank back on the bowl and insert the bolts you’ve removed previously.
Make sure you don’t overtighten the nuts, or the porcelain might crack.
What to Do When the Water Pipe Is the Problem
Sometimes, if you notice the toilet leaking through floor when flushed, you might be having an issue with the water supply line.
The same goes if you have a bathroom on the upper floor, then you notice toilet leaks through ceiling when flushed.
This could mean you have an issue with the pipe that connects the tank to the sewer system, either in the wall or underneath the toilet bowl.
Sometimes, the water might be just leaking from the fittings.
This is a good sign, as you can simply tighten them – once again, make sure you don’t go overboard.
However, if you have leaks in the water supply line and the pipes, this isn’t something you can fix by yourself.
It’s essential to contact the plumber as soon as possible, as only they can fix such damages.
Pipe cracks are no joke, and they can end up rather costly.
Some might even damage the entire structure of your home!
Because of this, you should take them seriously.
Even though the leak when flushing toilet doesn’t seem like a big issue, the truth is it can be.
A small leak or wet bathroom floor can be a sign of something much more severe.
Even if nothing’s terribly wrong with your bathroom, having stagnant water on the floor is never a good idea.
Try locating the source of the leak and see if you can fix it yourself using the tips we’ve given you.
If not, contact your local plumber as soon as possible to avoid greater damages.
We suggest Berkshire plumbing repairs in case that you are based in Uk.