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Toilet Tank Overfilling? Most Common Causes and Quick Troubleshooting Tips

by Blake Wiltshire | Aug 20, 2020 | Residential Plumbing, Residential Services | 0 Comments

Toilets are notoriously prone to plumbing issues. As necessary as they are, toilets can suffer from a number of problems, one of the most common being the toilet tank overfilling.

Toilets are made up of two major components: the toilet bowl and the toilet tank. The latter of which is usually the cause of any plumbing problems that your toilet may be having.

toilet tank

When the toilet tank overfills it can lead to lots of other problems, chief among them being flooding. Nobody wants to come home from work to find their bathroom flooded. A flooded bathroom could lead to you having to pay significant money for floor and wall repairs.

Along with an outright blockage in the waste line, an overflowing toilet tank is one of the more serious problems that your toilet could be having because it can waste water.

There are a number of common causes that can lead to this issue, but there are plenty of solutions as well. Some of these you can take care of by yourself, whereas others you will probably want to call a professional to come fix them for you.

This guide will help you diagnose the problem and figure out some possible solutions if you notice that your toilet tank is overfilling.

Most Common Causes for Your Toilet Tank Overfilling or Overflowing

There are two very common issues that could lead to your toilet tank overfilling. Because your problem likely stems from one of these two issues, it is fairly easy to diagnose what is causing the excessive water in your toilet tank.

A Misaligned Overflow Tube

When you flush the toilet, the rubber flapper which normally covers the flush valve is released. When this happens, the water that was previously resting in the toilet tank is forced into the toilet bowl at a high speed.

This is what causes the waste in your toilet bowl to be flushed into the sewer. After this process is complete, the toilet's fill valve, which connects to your house's water supply, fills the toilet tank back up with water, readying it for another flush.

If you remove the lid and look into your toilet tank, you will notice a white tube floating in the middle of the tank. This is the overflow tube. This is what prevents your tank from, well, overflowing.

The tube normally works by sending excess water in the toilet tank back into the bowl to stop it from either spilling over the sides or leaking through the opening where the flushing lever is located.

If the tube is out of alignment or is set too high, then it needs to be adjusted to the correct height so that it can properly deal with excess water. This can be done by using a hacksaw to cut the overflow tube and correct its alignment.

This can be done by yourself, but, if you're worried about cutting the overflow tube incorrectly or damaging other areas of your tank, you may want to consider calling the professionals at Althoff Industries to come out and do the job for you.

A Leaky Fill Valve

It is easy to recognize if your overflow tube is not functioning properly, because water will be spilling out the sides of the tank. However, if your overflow tube is working the way it should, but your toilet tank is still overfilling, then it will manifest itself as a different issue: a running toilet.

A running toilet describes a toilet that will not stop running despite the fact that it has not been flushed recently. This occurs because the fill valve, which is used to refill the tank, has been worn down over time and is constantly leaking water into the toilet tank.

Since your overflow tube is working, the excess water will not spill out the sides, but your toilet will continuously run due to the cycle of the toilet tank filling and emptying repeating over and over again.

In order to check your fill valve, turn off the water to your toilet by pulling the lever that is located behind the toilet bowl. Then, flush the toilet to drain the water out of the tank. Since the water is turned off, your fill valve will not refill the tank.

After you have taken care of these steps, take a look at the sealing around the edges of the fill valve. If you notice any cracks or chips in the seal, then you have discovered your problem. The fill valve needs to be replaced, otherwise, your toilet will never stop filling.

If this is coupled with a broken overflow tube, then it could cause a flood. A fill valve should only be replaced by a professional plumber. They will be able to replace the valve without causing any more damage.

Other Causes For a Running Toilet

A Faulty Flapper

A constantly running toilet can be related to other factors besides the fill valve. While these issues don't necessarily lead to overfilling per se, they can be the cause of a running toilet if you find that your fill valve is working just fine.

As we mentioned before, the rubber flapper covers the flush valve, which does the exact opposite of the fill valve. The flush valve pushes the water from the tank into the bowl to flush the waste away into the sewer.

However, if the rubber flapper is failing to work properly, water will continuously seep into the bowl causing it to run constantly.

If this is in fact your problem, then you should replace the rubber flapper in your toilet tank. It has probably become compromised due to wear and tear over the years. A new flapper should do the trick.

A Broken Ball Float

This issue is similar to the previous one. Older toilets used a ball float to control the flushing mechanism until the much more effective rubber flapper was introduced. Rubber flappers have replaced ball floats in newer models of toilets.

If you live in an old house with an older model of toilet, it is likely that you have a ball float and not a rubber flapper. If this is the case, and your toilet is constantly running, you will either have to purchase a new ball float or rubber flapper.

However, we recommend that you just go ahead and replace the ball float with a rubber flapper, as flappers are the newer technology and are far less likely to break again.

Althoff Industries has years of experience solving people's plumbing woes in the Chicago area. If your toilet has been afflicted by any one of these issues or is experiencing other problems, have us come out and take care of it today!

 

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