Water Level in Toilet Bowl Keeps Dropping (Causes and Fixes)

For a layman, diagnosing toilet problems is a difficult task. But, we encounter these problems in our daily lives. For instance, how would you feel if you enter the bathroom and are greeted with a bad smell? Then, you open the toilet and notice that the water level in the bowl is low. Does the water level seem to go down regularly? If so, you need to do something before it gets out of control.

So, in this article, we will go through the common reasons why the level of water in the toilet keeps dropping. The most common causes of water drops in the toilet bowl include faulty refill tubes, clogged air vents, and damaged flapper valves. In some cases, cracks in the toilet bowl also cause the water to leak out slowly, dropping the level in the bowl. We will also look at how you can fix each of these problems.

Cause # 1: Leakage in toilet Refill Tube

One of the common causes of the low water level in the toilet is a faulty toilet refill tube. The refill valve fills the toilet bowl once you flush the toilet.

man holding a faulty toilet refill tube
Image from Jim Eby

To find out if the refill apparatus is at fault, you need to open the lid of the toilet tank.  Flush the tank. If you notice the water leaking out of the refill valve, that means it is at fault. You need to replace it. Since water leaks out through the valve due to a breach in the diaphragm of the refill valve, the toilet’s bowl level stays low.

How to Fix the Toilet Refill Tube?

You can fix the Toilet refill tube by following these steps.

  1. First, you have to turn off the supply to the toilet.
  2. Then, flush the toilet once again to remove the water from the tank.
  3. Next, you need to loosen the foundation holding the refill valve.
  4. Now, the entire refill valve can be removed from the tank.
  5. Place the new refill valve in the hole from where you removed the previous one. And tighten up the foundation valve.
  6. Turn on the water supply. And flush the toilet.

The water level would have reached its position.

Cause # 2: Loose Float Ball

Besides the refill valve, another component that can reduce the water level in the tank is Float Ball.  The Float Ball regulates the amount of water in your toilet’s tank. It affects everything from tank water level to flush valve operation, and both of these are critical. The flush valve is responsible for flushing the toilet, and for draining and refilling the tank.

Sometimes, the Float Ball becomes loose or gets damaged in a way that makes it hard for water to drain. If the float and flush valve aren’t working, toilets will keep draining the water continuously.

So, following a flush, if your toilet bowl sinks or the water level keeps going down, it could be because of a loose or broken Float Ball.

How to fix Loose Float Ball?

To fix the faulty Float Ball, you can follow these steps.

  1. Open the lid of the toilet tank.
  2. Locate the Float Ball in the tank. It is in the center and is shaped like a small ball.
  3. Now, adjust the screw of the Float Ball. It can easily be tightened by fingers.
  4. Most toilet tanks have lines that show how much water is needed for them to work properly. Raise the Float Ball until the water slowly reaches the line.
  5. Place the lid back and flush the toilet again. See if the water level drops or remains constant.

Cause # 3: Blockage in Air Vent

Another cause of fluctuation in the toilet’s water level is the air vent. Every time a toilet flushes or the sink is flushed, vent pipes let in the fresh air. This helps the system move water through the drainage pipes. In addition, plumbing air vents keep sewer gases from coming into the house and let wastewater gas and odor go out. These pipes are placed away from windows and air conditioning units on the roofs so that the fumes can quickly spread.

If the air vent is blocked, apart from the low water level, the first sign you will notice is the smell; a rotten egg-like smell. Secondly, you will hear a gurgling sound on flushing the toilet.

How unblock the air vents?

To unblock the air vents, you have to go to your house’s roof and then follow these steps.

  1. First, you need to open the vent. There are often caps or other things that make it hard to see into the vent’s opening. Remove these to make the way clear.
  2. Using a garden hose, spray water directly into the vent.
  3. Take a 20 feet long auger; feed it in the vent and rotate it once you hit the debris.
  4. Keep turning the stick till the debris is removed.
  5. Spray some more water and see if it drains quickly.

Now, hopefully, the water level in the bowl would have been restored.

Cause # 4: Damaged Flapper Valve

Another component inside the toilet’s tank that is directly linked to the water level is Flapper Valve.

The flapper valve is connected to the flush lever with a chain. At times when the flapper valve’s seal gets a little weak, it causes the toilet water level to go down. So, to fix this problem you to replace that flapper valve seal.

How to replace the damaged Flapper Valve?

To replace the damaged seal, you can follow these steps.

  1. Cut off the supply to the tank, and flush the tank.
  2. Remove the tank’s lid and locate the flapper valve. It is at the bottom of the tank.
  3. Unhook the chain from the flapper valve.
  4. Take out the damaged flapper valve seal.
  5. Simply place the new seal and close the lid.

If the damaged seal is the cause of the low water level. Then, your problem would get resolved.

Cause # 5: Cracks in Toilet Bowl

It is not common, but it is also one of the causes your toilet bowl might be dropping water. The tiny cracks are hard to identify on the toilet surface. In addition, the water around the bowl is an indication of cracks.

To make sure that the dropping water level is due to bowl cracks, fill in the bowl completely by turning all faucets. Clean the floor. Then, wait and listen for a gurgling sound. If you hear a gurgling and notice water on the floor. Then, surely the bowl has hairline cracks and water is seeping.

Can the cracks in the Toilet bowl be repaired? How to replace the toilet?

You cannot repair a cracked toilet bowl. You have to replace it. To replace the toilet, follow these steps.

  1. Turn off the water supply to the toilet.
  2. Flush it to remove the remaining water in the tank.
  3. Using a sponge, drain the water from the tank and bowl.
  4. Unscrew the bolts from the base of the toilet.
  5. Remove it and install a new one.

Replacing a toilet is a difficult task, so it is advised to hire a plumber to do this task.

Summing up this article, we would suggest that if the water level in the toilet bowl keeps dropping. Then, firstly you can open the toilet’s tank and examine its components; refill tube, float ball, and valve flapper. In most cases, any of these components malfunctions. Similarly, a smell with a gurgling sound indicates a blockage in the air vent. And in rare cases, the toilet bowl may have cracks, which can be identified by the presence of sewage water on the floor.

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