Toilet Bowl Not Filling with Water After Flush (Why & What To Do About It)

Very few household problems cause as much worry as a toilet that refuses to work correctly. A toilet needs water flow to flush, so when the bowl isn’t filling with water, it can’t be used. 

A toilet that isn’t working causes everyone to go about their day differently, since we all need to be close to functional plumbing. This kind of disruption is very stressful, especially when you have few options.

The most common reason a toilet bowl won’t fill after flushing is that the float ball is positioned too low. Besides that, other components break over time and can also cause this problem. A flush assembly, fill valve, and overflow tube can prevent a toilet bowl from filling. 

Today, we’ll cover the 5 most common reasons (and solutions) for why a toilet bowl won’t fill after flushing, plus easy ways to fix it so that you can scratch this off your to-do list!

This is a common problem that will likely happen at some point, since components wear down and break over time. Luckily, toilets are designed in such a way that most of the required repairs are simple and can be completed within and hour.

5 Common Reasons Your Toilet Bowl is Not Filling Up

Float Ball is Too Low

This is the most common problem that prevents a toilet bowl from filling. All toilets either have a float ball, a float cup, or a float cylinder. Float balls are typically found in older toilets, while modern toilets have a small cup that performs the same function.

As is implied by the name, the ball, float, or cylinder floats on top of the water in the tank. This component is connected to the fill valve, and together they control the level of water entering the tank. Depending on the level of the water in the tank, the float mechanism closes or opens the fill valve by moving the float arm. 

To diagnose this problem, remove the lid to the toilet tank and have a look at the components inside. Observe the water line, which should be 1 to 2 inches below your overflow tube or fill valve. If your float mechanism is on top of the water, but the water level is too low, the culprit is likely the float device.  

Luckily, it is easy to reposition the float device and you don’t need any special supplies or tools. Simply change the height of the float arm that is attached to the float. These float arms are flexible, so you should be able to just bend it into a position that raises the float ball.

Do a couple of test flushes to see how the new positioning has changed the water level in the tank. You may need to adjust it a couple of times. Remember, 1 to 2 inches below the overflow tube or fill valve is ideal. 

Fill Valve is Misaligned

If it seems like your float device is in the proper position, your fill valve might be misaligned. 

The fill valve senses the water level in the toilet tank and controls the water flow into the tank.

If the fill valve is set too high or too low in the tank, the water level will either be too high or too low. 

To test whether the fill valve is the problem, remove the lid and observe the components. The fill valve is usually located on the left side of the tank, but this varies by model. Do a test flush and see where the water stops filling in relation to the position of the fill valve.

If you need to change the position of your fill valve, you’ll probably only need a screwdriver. This depends on what kind of fill valve your toilet uses, so be sure to inspect it before starting this repair.

To adjust your fill valve, first turn off the water supply to your toilet. This can be done easily by turning the knob attached to the water line going into the toilet tank. The water line will be coming from the floor or the wall near your toilet, and that is where you will see this knob.

Flush the toilet to evacuate the water from the tank. You will have to handle the fill valve, so you want water to be out of the way. 

Remember that if you want the water level in the tank to be higher, you will have to raise the fill valve’s position in the tank. This goes for all types of toilets and fill valves.

The process of adjusting the fill valve varies, as there are different designs on the market. It is best to do a bit of research on your specific device before attempting this adjustment. 

On most fill valves, there is a screw located on the right side of the device. Turning this screw clockwise will allow you to raise the position of the fill valve.

Raise the fill valve an inch at a time, turning the water supply back on and doing a test flush between adjustments. When the water level is optimal and everything is working normally, you’re done!

Flush Assembly is Damaged

There is a chance that your fill valve and float device have nothing to do with your toilet bowl not filling with water. As we know, most moving parts will likely need replacing at some point, and the flush assembly is no exception.

Also known as the trip assembly, this component includes all parts connected to the flush handle on the outside of the tank. To see the assembly in action, we can remove the tank lid and have a look inside.

The flush handle on the outside of the tank is connected to an arm inside the tank. The arm on the inside of the tank is connected to a chain, and this chain controls the opening and closing of the toilet flapper. 

If any one part of this assembly is faulty, the flapper won’t be able to open to allow water into the toilet bowl. To determine which part needs to be replaced, just press down on the flush handle. You’ll be able to tell if the handle has separated from the arm, or the arm has broken, or the chain has broken.

Luckily, it is very easy to replace these parts, and replacements are cheap. The flush handle and arm are sold together, so if one is broken you’ll have to replace both. If the chain is broken, you will only need to replace the chain. You won’t need any special tools, since everything either screws or clips together.

To get started, turn off the water supply to the toilet. Like we did to adjust the fill valve, just turn the knob on the water line going into the toilet tank. Now flush the toilet to get water out of the tank. You may have to reach into the tank and pull the chain by hand. Removing water from the tank isn’t necessary, but it does make things easier.

Now remove the broken part to be replaced. If this is the handle or the arm, unhook the chain from the arm, then turn the washer that connects the handle to the arm. If the chain is broken, simply unhook the chain ends from the arm and the flapper.

Once the broken parts are removed, you can replace them. A new handle and arm can be installed by connecting them through the hole in front of the toilet tank. Included in your replacement kit is a washer that goes on the inside of the tank. Screw this into position according to the instructions.

To replace a chain, simply hook the ends to the arm and the flapper. You should have a little bit of slack in the chain, and you can adjust the slack by moving the chain attachment to different holes on the arm.

Now you’re ready to test your new parts. Turn the water supply to your toilet back on, let the tank fill, and do a test flush. Watch the handle and arm to make sure they are moving in sync, and that the flapper allows the right amount of water to go into the toilet bowl.

If the handle and arm aren’t moving in sync, you may have to tighten the connection between the two, and if the flapper isn’t opening or closing for optimal water flow, you’ll have to adjust the chain.

If the flush assembly is working in sync and your water flow is good, your repair is complete.

Faulty Overflow Tube

Another important component that can break over time is the overflow tube. Like the flush assembly, this part controls the water levels in the toilet.

The overflow tube is usually located in the middle of the tank. This tube is set at a level that allows it to channel any excess water into the toilet bowl, which prevents the tank from overflowing. 

As we mentioned before, most parts will eventually break or malfunction over time, and the overflow tube is no exception. Diagnosing a problematic overflow tube does require a bit of a closer inspection, though, as isn’t as obvious as a broken flush assembly or poorly positioned float ball.

To diagnose this problem, remove the tank lid and locate the overflow tube. As we mentioned, the overflow tube is typically located at the center of the tank, and is inserted at the flush valve base. 

Inspect the tube for any defects. If you see a crack in the tube, this is likely to be your problem. 

Depending on your toilet, this is usually a very easy fix. With most toilets, all you need is a replacement overflow tube. 

As with most other toilet repairs, turn off the water supply to the toilet, and flush the toilet to clear the tank.

Using a replacement specific to your flush valve, insert your new tube. Reestablish the water supply to your toilet, do a couple of test flushes to make sure everything is working, and you’re finished!

Keep in mind that some flush valves have the overflow tubes permanently attached, so you may need to replace the entire flush valve mechanism. This is a more complicated process that you may want to hire a professional for.

Clog in Vent Stack

Unlike the other problems we discussed, this issue isn’t tied directly to the toilet’s inner functions. The vent stack is part of the greater plumbing system in your home, and problems with the toilet can be a symptom of a clogged vent stack.

A sewage vent is a pipe that’s attached to your drain network. This vent allows sewer gasses to escape the drainage system, allowing waste water to flow freely. 

The vent stack is the portion that is outside the house which releases the sewage gasses. You can see the vent stack on the roof of the house, and it usually has a cap on it. 

Debris, like leaves and twigs can clog this vent stack over time, trapping the sewer gasses. The trapped gas can keep your wastewater from flowing as it should, and this extends to the toilet. If your toilet is unable to drain correctly, water won’t fill the bowl to allow it to flush.

To diagnose this problem, you will need to inspect the vent stack. If you are comfortable getting on the roof of the house to do this, you can diagnose and repair the problem. However, if your roof pitch is too steep, or there are other safety concerns, this is best left to professionals.

If you want to do this yourself, make sure you have everything you need so you won’t have to go up and down the ladder. Supplies you’ll need include a flashlight, plumber’s snake, and a garden hose to flush the stack.  

Once you are safely on the roof, inspect the vent stack with a flashlight. A blockage will be apparent. Feed a plumber’s snake into the vent stack, pushing through the blockage by turning the handle. Pull the blockage out through the top of the vent stack.

To make sure the vent stack is clear of all debris, flush it with a garden hose. Your vent stack is now clear. 

When Should You Hire a Professional? 

For these easy repairs and simple replacements, you can definitely save a lot of money by doing it yourself. Replacement parts can cost as little as $10, while a professional service runs anywhere from $50 – $300. Keep in mind that some repairs are more complex, though.

It’s important to know when you should hire a professional in these cases. Some repairs, like a total flush valve replacement, are more complicated and require dismantling the toilet. 

Systemic problems like low water pressure can be caused by a variety of things, like bad pipes or mineral buildup. These are extensive repairs, and you can cause more harm than good if you don’t perform them correctly.

Professionals have the training and experience to deal with all types of problems, plus they have access to the necessary equipment and replacement parts. So, whenever you’re in doubt or if there’s a safety concern, be sure to consult a professional plumber before attempting repairs on your own.


It’s very common for a toilet to malfunction at some point during its lifetime. Remember, there are a lot of moving parts involved, and over time, everything breaks or warps. Luckily, a lot of these repairs can be done with a little knowledge and guidance.

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