Is Your Toilet Bowl Losing Water? There Is a Solution!

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Have you noticed that the water level in your toilet bowl keeps dropping? It’s not a big deal, but you don’t want to leave it like that — it might evolve into a major toilet incident.

Your toilet bowl can lose water due to a couple of reasons.

The most common issue is the blocked air vent, which causes the water to gurgle and makes a slight flushing noise during every flush. The second cause may be the bowl itself — it’s leaking, and you need to fix or replace it.

What can you do when this happens? Keep reading to find out!

Learn What Causes the Low Water Level

Before you begin repairing the toilet, it’s necessary to determine the root of the problem. Both problems demand different approaches, so let’s discuss each in detail.

Cause 1: A Crack in the Toilet Bowl

A crack in your bowl is always a possibility, especially if you have an older and worn-out model. It’s often easy to recognize a cracked toilet because it leaks and creates small puddles on bathroom flooring.

Leakages are bad for toilet performance, utility bills, and the environment, but they are easy to identify. Spotting leaks that flow down the drain — deep inside the bowl — is much more difficult because you can’t see anything.

In this case, you will have to try harder to identify the problem.

Cause 2: Clogs in the Air Vent

When you flush the toilet, waste and water flow down the drains and into the sewer. The flushing process is drawing air to leave a low-pressure zone in the waste pipes. The air vent balances the pressure, enabling the bowl to refill.

However, vents tend to collect debris because they are on the roof. Birds can build nests on the vent opening, while leaves from trees can block it too. If you don’t clean it for years — and you probably don’t — the vent will clog eventually.

How to Identify the Cause of the Low Water Level?

If you don’t see that your toilet is leaking at its base, you’ll have to conduct a little experiment. Don’t worry— it only takes a few simple steps:

Step 1: Check That the Tank Is Full

Open the lid to check if there’s enough water in the tank. Grab the lid on both sides with your fingers, and it should fall off instantly.

Step 2: Open All Faucets to the Maximum

Now you have to open all faucets in the bathroom to the maximum. Twist each knob counterclockwise, as you usually do when turning on the water.

Step 3: Pay Attention to Gurgling

When the water is on, you must pay attention to the sound of it flowing through the drains. In case the water is gurgling heavily, the problem lies in your plumbing vent pipe. If not, move on to the next step.

Step 4: Close the Faucets

The next task is simple — close the faucets to stop the water from flowing through bathroom pipes.

Step 5: Test the Water Level

Now it’s time to test the water level in your toilet. You should mark the current level on the porcelain and leave the toilet intact for an hour or two. Remember to wear rubber gloves — they will protect your hands from dirt, moisture, and debris.

Use a waterproof marker to draw a short line right above the current water level. Wait a couple of hours and check the water level — if it goes down while the faucets are off, there must be a crack somewhere in the bowl.

How to Fix a Toilet Bowl Losing Water?

You’ve probably identified the problem by now, so it’s time to fix the toilet and increase the water level. Two possible causes demand different solutions:

Option 1: Replace the Cracked Bowl

You probably won’t enjoy this, but it’s mandatory to replace a cracked toilet bowl. Start by preparing support tools like dry towels, rubber gloves, and buckets to help you cope with excess water and dirt.

After that, you need to close the main water supply line. It’s a small handle or knob behind your toilet — twist the water shutoff valve clockwise to turn off the water supply. 

Sometimes it’s hard to shut off the valve manually, so you can use an adjustable wrench to tighten the valve.

Flush the toilet to clean water from the tank. Now open the tank lid to pick the remaining water droplets with a sponge or dry towels. Finally, it’s time to uninstall the toilet bowl by following these steps:

  • Remove the water supply hose that leads water from the main drain to the tank
  • Unscrew tank bolts by turning them counterclockwise
  • Take out the tank bolts and remove the toilet tank
  • Unscrew a couple of bolts from the toilet base, use pliers to remove the caps
  • Gently move the bowl left and right to disconnect it from the ground
  • Dispose of the old bowl and prepare to install a new model
  • Repeat the entire process in reverse to reassemble the toilet 

Be careful when choosing the new toilet bowl because it has to match the dimensions of the existing elements. The safest option is to purchase the same item as it guarantees to fit the current setting.

Option 2: Clean the Air Vent

Cleaning the vent is simpler than replacing your toilet bowl, but it’s also more dangerous. That’s because the clogged vent is on the roof, so you must be careful and set the scene for safe work.

When you do that, take the garden hose and open the faucet. You might need someone to assist you because it’s impossible to handle everything safely from above. Push the garden hose into the vent and let the water clean it.

However, be prepared for a surprise — the water may backfire and spill out of the air vent. That means you have a clogged vent. In such circumstances, it is necessary to use a toilet auger and drill through the clog.

Insert the tool into the vent and rotate a handle to give it a push. As the toilet auger moves downward, it will spear through debris and decompose the clog. After that, you can pull it out and pour more water to clean the entire vent.

Other Issues With the Toilet Bowl

We discussed the two main causes of the low toilet bowl water level, but additional possibilities exist. A couple of those stand out:

Water Level Set Too Low

Sometimes the toilet tank doesn’t contain enough water to flush waste and leave enough water in the bowl. In this case, you can fix the fill valve quickly:

  • Open the toilet tank lid
  • Find the screw on the fill valve
  • Turn the screw clockwise to lift the fill valve handle

The fill valve controls the water level in the toilet tank. Lifting it will add a few more gallons to the tank, which means more water will reach the bowl as well. 

Fill Tube Is Not Working

There is a thin tube in the toilet tank, AKA the fill tube. It can detach from the larger overflow tube or damage after years of work. If this is the case, your toilet tank will not be receiving enough water to fill the toilet bowl.

The only solution is to repair or replace the fill tube. It’s easy to connect it to the toilet tank — pick it up and put the tube back on the rubber ring next to the overflow tube. If you purchase a fill tube, remove the old one and install the new item.

The Bottom Line

If your toilet bowl is losing water, you should fix it to avoid further damage. Make sure to identify the cause — is it the air vent system or a leaking toilet bowl? In each case, you can solve the problem by following our step-by-step instructions.

It will take some effort and elbow grease, but the most important thing is that you don’t have to call a plumber. If you like our tips, make sure to read more articles — Bomisch will give you many bathroom remodeling ideas.


Why does the water in the toilet bowl keep disappearing?

The water level in your toilet bowl can be lower for a couple of reasons. Firstly, the toilet bowl may have cracks that cause water leakages. Secondly, the air vent that regulates the pressure of the plumbing system may be clogged.

How do I fix the toilet from losing water?

If your toilet is using water, you need to identify the cause. It may be leaking at the base, somewhere in the drains, or from the toilet tank. Each problem demands a different approach and tools, so the safest choice is to consult a plumber.

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