8 reasons why your toilet tank isn't filling and what to do (2023)

Is your toilet tank not filling properly? If so, you are undoubtedly facing great inconveniences. Although such problems are common, you need to fix them as soon as possible. Not all toilet tank problems require a phone callprofessional plumber– sometimes you can read someToilet user manualsonline and just fix them yourself.

In this article you will find the top eight reasons for atoilet tank not fillingand what you need to do for each of them. But before that, let's take a look at exactly how a toilet works. You need to know the basics to successfully determine the cause of the problem at hand.

How does a toilet work?

Toilet tanks are designed to automatically fill with water with each flush. It typically takes about ten seconds to fill a tank completely, and the water level should be just below the overflow pipe. The tank has many moving parts that make it work - if even one fails, it can cause the entire tank to stop working properly.

When you flush, a handle arm pulls up a chain that connects to the flapper and flush valve inside the tank. This will dump all the water contained in the tank into the toilet bowl. Once the tank is completely empty, the flap covers the drain hole again and water begins to flow into the tank to refill it. A mechanism called a float ball determines when the tank is refilled.

8 reasons for an unfilled toilet tank

Because the toilet tank has so many different moving parts, the chances of one of them going bad is pretty high. If you're having problems with your toilet tank, the first thing you need to do is determine what's causing them. Below are the eight most common reasons your toilet tank isn't filling with water.

While some of them are not complex and can be fixed relatively easily, others require you to seek professional help.

8 reasons why your toilet tank isn't filling and what to do (1)

Before you start analyzing the problem, make yourself familiar with itdifferent parts of a toilet tank. Look up a chart online - going through the list below will be extremely helpful.

#1. Incorrectly adjusted filling valve

8 reasons why your toilet tank isn't filling and what to do (2)

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The fill valve is an assembly of tubes that regulates when a toilet tank fills or stops. Depending on the age and type of your toilet tank, the fill valve may look significantly different. However, if not set correctly, it can cause your tank to not fill up properly. Locate it and see if there is dirt or other obstructions in the pipe itself.

You should also check that the inflation valve is properly installed and has no visible cracks. There shouldn't be any water leaking out - if it does, you'll need to replace it with a new one. If the fill valve is intact, the problem may arise because it is too tight and will not allow the tank to fill properly.

Check to see if your fill valve has a screw at the top that regulates the amount of water that is let in. Turning it clockwise allows more water to flow in as the tank fills. Sometimes, instead of a screw, there is a clip on the side of the inflation valve. Adjust the amount of water by sliding it up for more and down for less.

#2. Low water pressure

If your toilet tank is filling so slowly that it feels like it's not filling at all, you may have a water pressure problem. In fact, low pressure can be a big problem not only for your toilet, but also for your shower, sink, and other appliances. Low water pressure is usually the result of a faulty water pump. If you live on the top floors of a taller building, you may also have water pressure issues.

Unfortunately, you cannot fix this problem yourself. The best solution is to install abooster pump, a task that only a professional plumber can handle.

#3. Broken toilet bowl

A cracked or damaged toilet bowl can cause water leaks, preventing the toilet tank from filling properly. Sometimes the cracks are small and are at the back of the toilet - so you can't see the water collecting on the floor. If you suspect your toilet bowl has cracked, make sure you don't use the toilet until the problem is fixed. It could collapse under you and flood your bathroom.

A broken toilet bowl needs to be replaced with a new one as soon as possible. Before contacting a professional, be sure to turn off the water supply to the toilet. You can do this either through the valve that connects the toilet itself to the plumbing, or through the main valve for the entire bathroom. Remember that damage to the toilet bowl can get worse if not fixed in time, so don't delay in replacing it.

#4. Worn flap valve

8 reasons why your toilet tank isn't filling and what to do (3)

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The flap valve is responsible for ensuring that the tank water does not run into the toilet when not flushed. It's a small rubber valve located at the very bottom of the toilet tank. If it's not working properly, it will affect how full your tank is and can even cause the toilet to run constantly. There are a few things that can go wrong with a flapper valve - let's take a look at the most common scenarios.

The flapper valve is usually held in place by a chain. However, if this chain gets misplaced and gets caught under the valve, it will prevent it from sealing properly. In addition, the chain can become worn or damaged - in this case you will have to replace it with a new one.

On some toilet cisterns, the chain is simply too long and cannot hold the flapper valve properly in place. In this case you will have to shorten it or replace it with a smaller chain.

The flapper valve itself can wear out just like any other part in the cistern. When the flapper valve hardens, it cannot seal properly, causing your toilet tank to malfunction.

The only thing you can do in such cases is to replace it with a new one. While not a difficult task, you might want to leave it to professional plumbing services such ashttps://www.lexsplumbing.com/– it all depends on your confidence when it comes to plumbing repairs.

#5. Damaged release lever

8 reasons why your toilet tank isn't filling and what to do (4)

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Another common cause of a toilet tank not filling is a faulty trigger lever assembly. In most cases, the part that connects to the handle has come loose due to corrosion or other damage. You can pinpoint the problem by removing the cover on your toilet tank and examining the trigger assembly. The problem can be easily fixed by getting a new part and replacing it.

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It's always a good idea to take a picture of the problem and show it to the staff at your local hardware store. They usually know exactly what it takes to fix the problem. If you don't want to do the replacement yourself, you can always call a plumber. A professional will have the parts and tools needed to properly replace your damaged trigger lever.

#6. Cracked or misaligned float arm or ball

8 reasons why your toilet tank isn't filling and what to do (5)

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In many toilet tanks, the fill valve is controlled by a float arm and ball system. If these components are damaged or worn out, it is likely causing your toilet tank to not fill. While setting up the float arm and ball system is fairly easy, there are several ways problems can arise. Plus, you can take care of almost all of the associated problems yourself as float arm and ball kits are available at most hardware stores.

Sometimes the float arm is not adjusted properly and will not let water into the tank. You can easily fix this by simply bending your arm up, which will elevate the ball to a new level. Some float arm and ball systems have screws that you have to tinker with to adjust the height. Feel free to test different positions until you find the one that works best.

If either the arm or the ball is worn out or broken, all you have to do is replace them. As already mentioned, you can get replacement parts at any hardware store. The float arm and ball systems are generally easy to install. However, if you are not comfortable doing it yourself, seek the services of a professional plumber.

#7. Damaged overflow pipe

8 reasons why your toilet tank isn't filling and what to do (6)

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The overflow pipe is a large pipe that carries excess water in the toilet tank to the toilet bowl to prevent overflow. It sits right in the middle of the toilet tank and is essentially a part of the flush valve. If the overflow pipe is damaged, it will result in your toilet tank not filling up while water continuously runs into the toilet. If this is the problem, your only option is to replace it with a new one.

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Fortunately, you can fix this problem yourself with relative ease. Simply pull out the overflow pipe and put the replacement in its place. Of course you need to make sure that the new hose is the same size as the old one. Alternatively, you can simply replace the entire purge valve mechanism.

#8th. Problem with the water supply

If your toilet tank seems fine but isn't filling up like it should, you may have a larger water supply problem. The first thing you should do is check the main valve that connects the water supply to your toilet. Is it in the open position?

You'd be amazed at how often this is the reason a toilet tank won't fill. The valve may have been accidentally closed by workers or children. If the valve is open, the problem could be more general.

Check if your sink is working properly. If there is no water there either, the entire water supply to your building may be disrupted. Check with your neighbors and local water authorities to ensure water is actually entering the building.

If your house is receiving water but not reaching your bathroom, it means you have a clog or a massive leak in your internal plumbing system.

Dealing with such complex plumbing issues should only be done by licensed professionals. If this is the reason your toilet tank isn't filling, contact a local plumbing contractor. The professionals know how to proceed and solve the problem.


So there you have it – the eight most common reasons the toilet tank isn’t filling and what you can do about it. Even though some of these problems may seem easy to solve, make sure you do your research.

You don't want to make the problem worse or accidentally flood your entire bathroom. If you're not comfortable with plumbing repairs, simply call a professional and let them do the job for you.

By hiring professional plumbing services, you can rest assured that they will find the root cause of your plumbing problems, rather than just implementing a "quick fix". In the long term, this can ensure your installation runs smoothly and can save you money on various regular repairs.

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If you are in the Sutton Coldfield area and need a plumber, contact 2nd City! They are industry experts with many years of professional experience. This way you can ensure that the work is done correctly, efficiently and to the highest possible standard. For more information on plumbing, seehttps://2ndcitygasplumbingandheating.co.uk/plumber-sutton-coldfield.


What would cause a toilet tank to not fill? ›

When a toilet is not filling up with water it is a sign of a faulty fill valve, wrong height of the toilet float, a leaking flapper, cracked overflow tube or low water pressure.”

What triggers a toilet tank to fill? ›

The fill valve (sometimes referred to as a ballcock) brings water into the tank after the toilet is flushed and stays on until the tank refills. Any time water exits the tank (such as when a flapper is leaking), the fill valve will turn on in order to maintain the water level.

How do you fix a toilet that won't fill up fast? ›

In any case, these are the four solutions you can try to get your toilet working properly again:
  1. Clear the clogged vent. If the vent is clogged, use a pair of needle nose pliers to pull out anything that's in there. ...
  2. Clear the clogged drain. ...
  3. Fix any leaks in your plumbing. ...
  4. Remove any blockage from the pipe.
Dec 30, 2021

How do I get my toilet tank to fill more? ›

Decide whether you need to raise or lower the water level. Locate the screw that attaches the float to the fill valve (usually on top of the fill valve). Using a screwdriver, turn the screw in small increments to adjust the water level. Clockwise will raise it and counterclockwise will lower it.

Why is my toilet bowl not filling with water after flush but tank is full? ›

If a toilet is in perfect condition but does not fill up with water after flushing, you probably have low water pressure. Old rusty pipes and leaking pipes are the most common causes of low water pressure in homes.

Why won t my toilet tank refill after flushing? ›

Check the toilet float and fill valve

If water goes into the toilet but doesn't fill it all the way, the problem is likely with the float or fill valve. Flushing the fill valve will remove debris that might be causing it to clog and the tank not to fill up.

How do I know if my fill valve is bad? ›

Warning signs that your fill valve is bad are the constant sounds of running water from the tank and an ineffective flush. You can troubleshoot by adding a few drops of food coloring to the tank. If you do not see the food coloring leak into the bowl, then the fill valve needs to be replaced.

How do you know if your fill valve is bad? ›

Warning signs that your fill valve is bad are the constant sounds of running water from the tank and an ineffective flush. You can troubleshoot by adding a few drops of food coloring to the tank. If you do not see the food coloring leak into the bowl, then the fill valve needs to be replaced.

Why is my toilet water valve open but no water? ›

If no water comes out the opening with all of the fill valve parts removed, then there is a clog in the line to the fill valve. The next step is to shut off the water and remove the supply line from the bottom of the toilet, then redirect the supply line into your small bowl and turn the valve back on.

How much does a plumber charge to replace a toilet fill valve? ›

According to Fixr, the average toilet valve repair cost is between $75 and $200 to replace a flush valve or up to $400 to fix a constantly running toilet. This includes the cost of the plumber's time for the toilet repair and the cost of the toilet parts.

How do you clean a toilet fill valve? ›

Cleaning your fill valve

Once a year, or if the fill valve will not turn off, remove the cap assembly and inspect for debris in the valve body seat. Use an inverted coffee cup over the uncapped valve body and turn the water on all the way for three or four seconds then turn off. Do this twice to rinse out the valve.


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