Why Your Toilet Tank Is Not Filling Up And How To Fix It?

We’re guessing that if you’re reading the article, you’ve just flushed your toilet, and to your disdain, it hasn’t worked.

Why Your Toilet Tank is not Filling up and How to Fix it

For some strange reason, it simply won’t flush. Your first reaction might be to panic, because who wants the hassle of a non functioning toilet? 

Don’t worry though, as I’m sure many of you reading will be pleased to know, a toilet not flushing properly, or a bowl that takes a long time to refill is actually a common problem dealt with by plumbers.

If you want to find out some causes behind why your toilet might not be functioning properly, as well as some helpful ways to fix this issue, keep reading, as we take a look below. 

Why Is The Toilet Not Filling Up With Water? 

So this is the main question, why isn’t your toilet filling up with water like it usually does when you flush? 

First of all, let’s take a look at the facts. A toilet tank is designed specifically to fill up with water every single time that it’s flushed.

In terms of water level, this should be at approximately ½ inches below the overflow tube and take around ten seconds to completely refill again. 

If your water is taking longer than this, or it’s simply not refilling at all, you’ve got a problem on your hands. 

There are a whole host of reasons why it might not be filling up. Sometimes it can be due to a faulty valve, issues with the pressure of the water, wrong toilet float height, cracked overflow tube, a leaking flapper, or issues with the sewer line itself. 

Don’t lose heart, there are lots of things that you can do to fix each of these issues.

Keep reading as we’ve compiled a helpful guide on how you can get your toilet flush back into regular working order. 

Check The Pressure Of The Water

One of the first things that you can do to try and get your toilet back to working normally is checking the water pressure.

At first, this may seem like a too-obvious thing to check, but you’d be surprised how many times this problem is actually the culprit. 

If the water pressure isn’t high enough, then it will simply shut off before it gets the chance to fill up your tank.

An easy way to check if this is actually the culprit is to try some of the other water sources in your home.

Go into the kitchen and turn on the tap there to see if the water flow is normal. 

If the water isn’t working in the entire home, then it’s a problem with the water supply in general, but if it’s just not reaching your bathroom, then there could be a potential blockage or leak in the plumbing system.

Blockages are often caused by old and rusty pipes, or ones that have been clogged.

To check if this is the problem, remove the fixture and blow some air through it.

If it seems to be fine, then it’s caused by the main water system instead. You can call up your local plumber to help you with this issue. 

It might also be due to a failing water pump, especially if this is happening to some of your neighbors in the same building.

To solve this problem, you will need to call your water company. 

Check How Your Float Ball Is Seated

Another common problem experienced by toilets is how the float ball is positioned.

Even if you have a brand new toilet, they all come with a float ball or cup positioned inside.

Cups are usually fixed in newer toilets, whereas balls make up the older versions. 

This is one of the first things that you should check for if your toilet isn’t performing properly, as float balls are responsible for regulating the water inside your tank. 

They can become misplaced and deviate from their position above the water. Check if the ball is seated too low in the tank, as this will likely be the cause. 

How To Adjust The Float Ball?

How To Adjust The Float Ball 
  1. To Adjust your float ball and get it functioning properly again, first turn off the water supply on the shut off valve.
  1. Hold the lever of your toilet, and then hold it for long enough so that most of the water escapes. 
  2. Remove the lid of the tank and set it aside carefully, then look inside to find your float ball or cup. 
  3. If you have a float cup contained inside, then turn the long plastic screw that is connected to the float in a clockwise direction. Use a screwdriver to do this. 
  4. If you have a ball inside instead, then look for a screw that connects the fill valve to the float arm. Turn this screw in a clockwise direction. 
  5. Like we mentioned before, the water should be about ½ inches below the overfill tube, so adjust it slowly and carefully until it reaches this height. After this, simply place your toilet tank cover back on. 

Replace The Toilet Flapper

Another issue that could be causing your toilet to stop working is a non-functional flapper.

This refers to a rubber seal which is situated at the bottom portion of the tank.

When the toilet isn’t being used, the flapper prevents tank water from emptying into the toilet. 

It could be causing you issues because the chain which keeps it in place has become tangled.

This could get caught beneath the valve, and prevent it from being sealed efficiently.

The leaking flapper could also simply be caused by its becoming old and worn out. They can potentially corrode and harden, causing them to be completely non functional. 

If this does seem to be the issue, then you can actually replace the corroded flapper yourself fairly easily. 

How To Replace A Toilet Flapper?

  1. The first thing that you need to do when replacing the flapper is to turn off the water valve and flush your toilet. 
  2. Remove the lift chain from where it is situated over the handle (Check out this Step-By-Step Guide For Replacing A Toilet Handle). 
  3. Remove the pegs, thereby detaching the flapper from the overflow tube. Hold the pegs together, and proceed to lift them. 
  4. Ensure that there is no leaking by turning the water valve back on. 

A Damaged Overflow Tube

The struggles that you’re currently facing with your toilet flush may be caused by a damaged overflow tube.

The overflow tube is the item responsible for moving the excess water in the toilet tank to the bowl so that it doesn’t overfill. 

Sometimes this tube can actually crack, which will either cause the water to fill up, but past the normal level causing it to overflow, or the water will not get drained to the hole at all which will again cause it to overflow. 

To see if your overflow tube needs to be replaced, remove the lid of your toilet tank, then turn off the water supply.

Remove the plastic outlet ring, the washer and the screws surrounding it that secure it in place.

You can then proceed to pull the tube out from where it is situated, then install your new tube. Be sure to use a screwdriver to perform this task. 

After you’ve undertaken these steps, you can go ahead and turn the water back on to see if it’s filling up to the right place. 

Misadjustment Of The Fill Valve

Another common problem that you may be experiencing is a misadjusted fill valve.

The fill valve is the part that is responsible for connecting your toilet tank to the supply of water.

After you are done flushing, this item will fill up your tank with water again. When you flush, the float will move to the very bottom of the tank, allowing your fill valve to be opened. 

The float will gradually move upwards at a slow rate until the tank is filled with the correct amount of water again.

The refill tube is responsible for sending gradual amounts of water to the bowl of the toilet to prevent glasses from the sewer from entering the room. 

The fact is that if your fill valve isn’t working properly, your tank cannot be filled up with water again.

It might fail to work for a number of reasons, sometimes it’s because it’s become filled up with debris or simply gotten too old. 

If you suspect that the reason is because of debris because your toilet is brand new, then there is a way that you yourself can replace this item. 

How To Clean The Fill Valve?

  1. In order to replace your fill valve, the first thing that needs to be done is shutting off the water supply and flushing the toilet to clear it from water. 
  2. After this, hold the shaft of the fill valve with one hand right at the very bottom of the valve. Turn it ⅛ counterclockwise, before proceeding to remove it completely. 
  3. Take an empty cup, and place it over the fill valve to prevent water from filling up and splashing. Turn on your water supply and the pressure will get rid of all the debris from your valve. 
  4. Once it has become completely unblocked, you can put the cap of the fill valve back on again. 

If however, you’ve taken the lid of your toilet off and have found that the fill valve looks incredibly old and worn, then it’s definitely time to replace it. 

How To Replace The Fill Valve?

  1. Take the same first steps once again, and turn off your water supply before proceeding to flush the toilet to clear it from water. 
  2. You will see the coupling that is responsible for the connection between the water supply line and the toilet tank. Turn this counterclockwise and remove it to disconnect the water supply fully. 
  3. To uninstall the lock nut from the tank, simply turn it in a counterclockwise motion. 
  4. Proceed to detach the overflow tube from the fill tube, and lift the fill valve carefully. 
  5. Place in your new valve and screw the lock nut back into place
  6. You can then connect the water supply, before installing the new fill tube to the overflow tube. 
  7. Turn on your water supply and see if the water levels are adjusted properly. 

Damaged Toilet Bowl

Again, this may seem like an obvious one, but one of the first things that you should do if your water is not filling up properly is to check if the toilet bowl is damaged. 

It might have a crack in it that’s stopping that could be causing a leak, resulting in the bowl losing water as it’s being filled up.

You might not be able to see the crack initially, but be sure to check the back of the bowl, as the crack might not be immediately visible. 

This could be a potentially dangerous situation as using the toilet in this condition could fill your bathroom with water.

In order to avoid this, turn off the water supply, and stop using it until it’s fixed. 

You can actually easily fix this problem yourself by replacing the overflow tube.

Take care when you’re purchasing a new tube that it is the exact same size as the last one so that it fits properly. 

Final Thoughts

Although the natural instinct when your toilet tank isn’t filling up is to panic, there’s really no need to worry.

Most of the common causes outlined above can be easily fixed without even needing to call a plumber in.

All it takes is a bit of time and patience. If you suspect that the problem is with the water supply itself, then you can go ahead and call somebody to help resolve the issue.

Adrienne Carrie Hubbard
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