The Causes Of Low Water Levels In Toilet Bowl And How To Fix It

Typically, there should be three cups of water in your toilet boil, just before you get to the toilet trap.

Low Water Levels in Toilet Bowl

This water is very important because it acts like a seal to keep away all of the bad smells in the drainpipe so your house can smell lovely and clean.

However, sometimes you may find that the water level in the toilet bowl has been reduced significantly.

This is a common problem that is better to fix as soon as possible. 

In this article, we will discuss all of the causes of a low water level in your toilet bowl, as well as all of the ways you can fix it!

So, if this is of interest to you, read on for more! 

Causes And Solutions Of Low Water level In Your Toilet Bowl 

Let’s check out the causes of low water levels in your toilet bowl, and the solutions, in more detail!

The best thing to do if you find yourself with less water in your toilet bowl than there should be is to fix the issue before it gets out of hand. 

Cause: Faulty Fill Valve 

The first cause of low-level water in the toilet bowl is a faulty fill valve, whether it has been damaged or merely positioned poorly.

The fill valve is supposed to control the amount of water that flows into the tank once the toilet has been flushed.

So, when you place the fill valve in the incorrect place, it will not allow this to happen and you will have a low supply of water in your toilet bowl as a result. 

Solution: Faulty Fill Valve 

Luckily, this problem has a quick and easy solution!

All you need to do is change the position of the faulty fill valve in order for the water in the tank to be raised.

Now, the way you adjust the fill valve all depends on the type of valve you have.

Here are more details on how to adjust the most popular kinds of fill valves! 

Float-Cup Fill Valves: To adjust float cup fill valves, you will need to check if yours came with a plastic screw mechanism when it first arrived.

If it did, then this is what will permit you to simply slide the float up.

This will raise the level of water in the bowl. 

Other types of float-cup fill valves will have arrived with a metal spring clip.

You need to pinch this clip in order to ensure you are able to raise the float.

The float must reach the rod in order for the water level to be raised. 

Piston/Plunger And Brass Diaphragm Ballcock Valves: With these valves, you need to bend the float rod upwards in a gentle manner, which will cause the water level in the tank to increase. 

Plastic Diaphragm Ballcock Valves: These valves typically come with an adjustment screw on the top of it that will change the height of the ball and float rod.

Turn the screw counterclockwise with a screwdriver if you want the water levels in the tank to rise. 

Internal Float Fill Valves: With these valves, you need to twist the fill valve’s top head counterclockwise to get it to unlock.

Then, you will need to move the whole head upwards to ensure the tank’s water levels will be raised. 

Pressure-Activated Or Floatless Fill Valves: In order to access these valves, you first need to totally empty your toilet tank.

Then you should be able to see an adjustment screw at the top of the valve.

This adjustment screw needs to be turned clockwise. Do this, and the water in the tank will be raised. 

Please note that you may find there are other issues with fill valves that cause them to not work properly Let’s check them out below 

Cause: Fill Valves With A Stuck Metal Diaphragm 

These fill valves usually rust as time goes on because they are generally made from cast brass.

The Causes Of Low Water Levels in Toilet Bowl And How To Fix It

Because of this, the metal arm of the valve will get stuck, which causes the floating ball to go stagnant. 

Solution: Fill Valves With A Stuck Metal Diaphragm 

To fix this issue, you will need to clean the rust and then adjust the fill valve as mentioned above.

It is also a good idea to change the fill valves from brass to PVC because these will be rust-resistant and durable. 

Cause: Damaged Fill Valves

Over time, fill valves will grow old and damaged and this results in leaks, amongst other issues. 

Solution: Damaged Fill Valves

If your fill valve is damaged, then the best thing you can do is get a new one as a replacement. 

Cause: A Cracked Toilet Bowl 

Sometimes, you may find that there is low-level water in your toilet bowl because there is actually a crack in the bowl that causes water to leak out.

Cracks can form anywhere in the toilet bowl, from the back, sides, or base. 

It is often the case that these cracks are very difficult to find, and this is going to be even more true if they are small, inaccessible, or hidden. 

However, a good way to tell if there is a crack in your toilet bowl is to see if there is any water on the floor surrounding the toilet.

This is clear evidence that, somewhere, there is water dripping onto the floor as a result of a crack or leak in the bow. 

Solution: A Cracked Toilet Bowl 

Because various people sit on the toilet bowl a day, the toilet bowl actually handles a lot of weight.

So, if there is a crack, it shows that the bowl is coming to the end of its life and it is better to replace it than to try and fix it.

However, this may prove to be a very expensive solution, particularly if your toilet is a one-piece. 

So, you may be glad to hear that there might be another solution, particularly if it is only a small crack.

It may be a good idea to use a plumber’s putty to seal up the crack, provided that the plumber’s putty is waterproof! 

If you want a good waterproof plumber’s putty suggestion, then click this link here! 

However, it is important to note that a sealant is only a temporary solution, even though it might work well.

This means that there will come a time when you have to fix the toilet in the future.

So, it may still be the wiser choice to replace the bowl as a whole. 

If you do decide to replace the bowl, then it is best to call a plumber to do it for you. 

Cause: Damaged Fill Tube 

The fill tube, also known as a refill tube, is a small plastic hose in the toilet tank that links the tank and the tube together.

It is supposed to control how much water flows through the tube and into the bowl every time the chain is flushed.

However, when it does not work properly, it results in there being too much or too little water in the bowl. 

Then, over time, the tube and the overflow tube can actually separate, which leads to the toilet tank filling up with water and then stopping the water from flowing before the bowl can be filled with the correct amount of water again. 

Solution: Damaged Fill Tube

The best thing to do if you suspect you have a damaged fill tube is to open the tank and inspect it to make sure it is clipped onto the overflow tube correctly. You should also check for damage at this stage. 

If you see that the fill tube is worn down, then, unfortunately, you will not be able to fix it. It will need to be replaced as soon as possible.

The Causes Of Low Water Levels in Toilet Bowl And How To Fix It

However, if you notice it is in good condition and has simply become disconnected from the overflow tube, then you can go ahead and connect those together by clipping the fill tube to the overflow tube.

Cause: Partial Clog In The Toilet Trap 

If there is a clog in your toilet, then in the trap of the toilet there will be a siphoning effect.

This is where drainpipe waste will sip on the water in an attempt to get itself unclogged.

So, chances are, the water will have been sipped so much that it becomes low enough that it affects the amount of water in the bowl. 

If you suspect this may be the cause of the low level of water in your toilet bowl, then you need to flush the toilet and see what happens.

If there is a partial clog in the toilet trap, then the water will overflow until it reaches the toilet rim.

Then, it will sip back slowly until it goes beyond the typical water level. Sometimes, the bowl may even drain in its entirety. 

The cause of the partial clog can vary. It can be anything from a tampon to biodegradable waste, foreign objects, and much more. 

Solution: Partial Clog In The Toilet Trap

The first thing you need to do to fix this issue is to check the toilet trap.

When you find the cause of the partial clog, then there are a few things you can do. They are: 

  • For large waste items like diapers: Put on some rubber gloves and then remove the item with your hands. 
  • For tough clogs: Use a snake or an auger 
  • For biodegradable waste: find a bucket and fill it with around five gallons of water. Pour this water into the bowl quickly. Alternatively, you can use bleach, baking soda, or vinegar. For biodegradable waste, you have the option of using a plunger, too. Check to make sure there is no water backup. 

Cause: Clogged Or Dirty Siphon/Rim Jets

Rim or siphon jets can be found under the toilet bowl rim.

They are openings that allow water to enter the bowl from the tank when you flush the toilet. 

When these openings become clogged or dirty, then there will not be enough water flowing into the bowl.

In addition to this, the water pressure will also be low, which results in the flush being weak and a low-level amount of water in the toilet bowl. 

Solution: Clogged Or Dirty Siphon/Rim Jets

First, you need to ensure that the tank is clean by inspecting where the blockage or dirt is coming from.

Then, you must scrub the siphon or rim jets with a vinegar solution.  This should get the water level in the toilet bowl back in working order again. 

Cause: Blocked Sewer Vent Pipe

The vent pipe system in the toilet also works to regulate the air pressure (No vent in your toilet? Learn more here).

It will play a part in how the water will move through the pipes, on top of removing odors and gas from the house. 

So, if there is ever a blockage, then the vent pipe attempts to find air from other sources in the home.

This will result in gurgling sounds as you hear both air and water being siphoned. 

Other times, after you flush the chain, water will exit the bowl very quickly and this results in an empty toilet bowl.

After this, you will hear further gurgling noises that can be accompanied by bad smells.

If this happens, then you know the air seal is damaged or broken and the pipes no longer have any suction. 

Solution: Blocked Sewer Vent Pipe 

The best thing to do in this situation is to climb to the roof and clean out the vents.

This will permit air to flow freely and cause the air pressure to be balanced once more.

However, if you cannot reach the blockage, then the best thing to do is call a plumber so they can fix the solution for you. 

If blockage in your vent pipes is something that happens regularly, then it is best to get a cover for them to prevent things like branches or leaves from getting stuck inside. 

Final Thoughts 

Low-level water in the toilet bowl is inconvenient, especially when there are so many different causes, such as a blocked sewer vent pipe, a partial clog in the toilet trap, or even a fatal crack in your toilet bowl (Check out Replacing Clay Or Terra Cotta Sewer Pipes). 

However, even though there are many issues you could experience with your toilet, there are also many solutions, most of them quick and easy foxes.

However, there are also instances where you will need to replace the toilet as a whole or call a plumber to fix an issue. 

Whatever the case, you can rest assured knowing that your toilet issues can be fixed in no time at all!

Adrienne Carrie Hubbard
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