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How to Troubleshoot an Overflowing Toilet

A slowly overflowing toilet is like a slowly dripping tap – you pay it no attention until the running water is halfway up your boot. Then, all of a sudden, you’re spending half an hour with your head in the ceiling and wondering why on earth you didn’t decide to DIY last year.

The longer you leave an overflowing toilet, the worse it gets. And that’s bad for two reasons: firstly, the toilet starts stinking up the house pretty quickly, and secondly, water damage can lead to some serious problems if left untreated. A slow drip will become a torrent in next to no time at all, so here are our tips on what you should do if your toilet is overflowing.

A slow-running toilet can be a really annoying problem to have in your home because, well, it’s kinda gross. So today, we have Vlad from Mister Plumber (a GTA plumbing service) to share with us a few ways you can stop it from running and prevent any overflows!

Using a good ol’ fashioned plunger

One of the most common culprits of a clogged toilet is a jammed pipe that can be freed with a plunger. This is a tried-and-tested method for clearing all types of blockages in toilets.

The steps are simple: firstly, make sure that any water in the bowl has been flushed out. Then, fill up a bucket with water and plunge it into the bottom of the toilet.

Push down for 10-15 seconds to clear any blockages, then flush away excess water. You might have to repeat this several times until you’re sure that your blockage has gone.

Now that you’ve stopped the overflowing, your next step should be to get that plunger out and give it a good clean. If you’re not very particular about how it looks, then don’t worry too much – but if you want it to stay in tip-top condition, we’ve got some tips on cleaning plungers for you here.

Checking the float

When your toilet keeps running, the float may be too high. The float is usually attached to a rod that extends from the tank into the bowl. It floats so it can turn off the water supply to the tank when the bowl is full of water.

If you have adjusted this level before and the toilet keeps running, there might be a problem with the float. Run your hand along the rod until you can hear water running through it. You may have to adjust the level of the rod so that any residual water will drain into the bowl and stop overflowing.

Checking the rubber flapper

If you have a rubber flapper that is the problem. This flapper is at the bottom of the tank and it lifts up when you flush to allow water from the tank into the bowl. If it doesn’t lift all the way up, some water will remain in the tank. This can lead to excess water in the bowl after you flush. Make sure that it is attached properly and lifting up completely before each flush.

Checking the chain

If you know you have adjusted the rod level correctly, but there still seems to be some excess water in the bowl every time you flush, then it’s probably because of a chain issue.

There should be a chain hanging from the handle which links to the flapper. If it is not in contact with the flapper, then the tank will continue to fill after you flush.

You can easily adjust this by sliding some links further down until you hear them drop onto the flapper.

Checking for cracks in the tank

Finally, cracks in the tank can cause water to leak out and pool in the bowl. This might happen if your toilet is very old or was installed improperly. If this is the case, then unfortunately you’ll either need to replace it or live with a permanently wet floor.

That should solve your problem, but if you have any more problems with it overflowing or something else goes wrong, contact a plumber. If you think your toilet is in need of maintenance, then you can give your local GTA emergency plumbing service a call to book yourself an appointment with a professional.


If you have tried all of these steps and your toilet is still overflowing, then it might be time to call a local specialist like Mister Plumber. They can come and inspect your home’s plumbing system for you, to find out what the problem is. They will be able to give you a clear diagnosis of the state of your toilet and recommend any repairs that are needed.

Whatever method you use to stop an overflowing toilet, it’s important that you do not ignore this issue: it can quickly lead to an overflowing bath or sink, creating a much larger, and messier problem.