Plumbing Tips

Toilet Leaks When Flushed

We tend to postpone taking care of a toilet which leaks only when flushed in favour of more urgent matters. However, if left untreated for a long time, the leak will get worse and might result in water damage and even a flood. The following repairs of your home would amount to a large sum of money and an irate downstairs neighbour.

So if:

  • Your upstairs toilet is leaking through the ceiling of the room below it;
  • You find a pool of water around the toilet every time you flush,

The read along!

Table of Contents:

Toilet leaks at the base when flushed

If you find a small pool of water around your toilet after each flush, it’s most likely leaking from the base. Do not ignore this problem, as the water from the bowl is not sanitary and most likely smells terrible. Not to mention it can also attract pests, yuk.

  • Check your toilet to make sure the leak is not coming from somewhere higher up and dripping down the bowl.
  • Wipe up the water pool with an old rag and dry it thoroughly with a dry one.
  • Wipe the bowl as well. This test will not only show where the water is coming from, but also rule out condensation on the toilet bowl.
  • Flush.
  • Listen and watch carefully as water on the floor collects again. If the pipes and tank are dry and no dripping is heard from them, then your toilet is leaking at the base. 

There may be two reasons for this:

The bolts are loose

The two bolts on the left and right base side of your bowl should be firmly screwed to the floor. This is so the wax ring under them forms a water-tight seal. If they’re even slightly loose, you will experience leaks every time you flush. Fortunately, this problem is easy to fix:

  1. Remove the caps with a putty knife.
  2. Tighten the bolts a little at a time. Go from one to the next with every turn, so the bowl is properly balanced.
  3. Do not be tempted to overdo it; otherwise, you might crack the base of the bowl.

* If you screw, but don’t feel the bolts tightening, then it is likely you need to replace them entirely.

The wax ring has gone dry

If the bolts are fine, but water still comes out from beneath the base, then it’s probably the wax ring that needs replacing. It’s found below the toilet, connecting its waste hole to the drainage system. It needs to be tightly sealed. Otherwise, water will bleed through. Even if it’s been installed correctly, over time it does deteriorate, so you’ll have to replace it.

  1. Turn off the water supply.
  2. Flush the tank and sponge out the rest of the water remaining in the bowl.
  3. Disconnect the water supply line from the toilet.
  4. Unscrew the bolts on both sides of the base.
  5. Grab the toilet by the centre and push it gently from one side to the other to break the old wax seal.
  6. Grab the base of the toilet (and not the tank) and lift it. Place it on one side.
  7. Scrape the old wax ring from the flange with a spatula. Besides around the drainage hole, it has probably left some residue on the bottom of the toilet. Make sure to get that, too.
  8. Put the toilet back into position, and make sure it sits sturdy on the ground and not rocking to one side. Otherwise, you’re going to have to shin it after installing the new wax ring.
  9. Unpack the new seal wax and place it on the flange. Gently press it down to secure it in place.
  10. Place the toilet back on and sit gently. You have to feel the new wax ring being squished down, otherwise, it won’t seal properly.
  11. Screw the bolts back on and reconnect the water supply. You’re good to go!

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Toilet leaks from the tank when flushed

If it turns out the bolts and the wax ring are not responsible for leaks after flushing, then water might be leaking down from the tank. There are two areas which could be the source of the problem:


If you find water leaking from the toilet bowl and tank after flushing, it’s most likely a worn-out gasket. To check and replace if needed, you will need to disconnect the tank. Because of the heavy weight of the tank and how hard it is to detach it, it’s recommended you find a second person to help you with this task.

  • Turn off the water supply and flush the tank of any liquid. Make sure you remove any remaining water by using an old sponge.
  • Detach the house carrying water from the tank to the bowl.
  • Loosen the bolts which hold the tank and bowl together. These are situated at the back of the toilet.
  • Lift the toilet tank and place it on the ground.
  • If the gasket is dry and showing even small cracks, you need to replace it. If not, the problem lies somewhere else.
  • Remove the old gasket. Do not throw it out; you will need it as a reference when you go to the hardware store to buy a new one. The new one will look slightly smaller, but that’s normal because the old one is stretched out.
  • Put the new gasket in its place and put everything back the way it was. Be careful not to overtighten the bolts.

Water supply line

Water might be leaking down the supply line from the fittings, or from small holes which have sprung over time. Tear a small piece of toilet paper and run it down the water supply line. Check for damp areas. It’s better to use toilet paper because it’s easy to see if it gets wet. Otherwise, it can be hard to tell if you actually feel moisture or just the coldness of the line. After all, it is full of cold water.

If you find leaks from the fittings, you need to tighten the nuts gently with a wrench. Do not overdo it, as it will result in greater damage later on.

If you find holes in the supply line itself, you’d be better off replacing it altogether before the leak gets really worse and results in potential flooding.

If you need to learn more about this topic, check our post on how to fix a leaking toilet tank.

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Call in the professionals

If after all this you still can’t find the source of the leak after you flush the toilet, then maybe you should consider professional help. Fantastic Services works with excellent plumbers who have plenty of experience and always come fully equipped to tackle any leaks. Your leaking toilet will be good as new once the pros take care of it.


  • Do not ignore the problem.
  • Check if the bolts on the toilet base are well tightened.
  • Check wax ring below the toilet.
  • Explore the toilet tank for a worn-out gasket or water supply line.


Do you have or have had a toilet leak? How did you manage to fix it? Let us know by leaving a comment.

Image Source: Shutterstock / cunaplus

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