Toilet Tank Water Loss: Causes and Fixes for a Common Problem

Toilets are one peaceful spot in the entire home until an issue comes up and takes a massive toll on you. One of the common issues is when toilets start to lose water out of the blue, leaving you and your utility bills flabbergasted. “Why does my toilet tank keep losing water?” – do you ask yourself this question all the time but do not know the exact answer?

We’ve got your back, buddy!

There can be several reasons for a toilet tank to act up and cause drama. Fortunately, most issues are easily fixable.

This article will detail WHY toilet tanks keep losing water and how you can identify the problem and actively fix it.

Do not miss out on any points unless you enjoy a toilet that keeps losing hundreds of gallons of water every single day because of a leakage issue.

Causes of a Toilet Tank Losing Water

A toilet tank that keeps losing water is a pain in the neck.

What is/are the reason/s for this stressful issue? Let’s break it all down.

Error in the supply line

The first and most likely cause is an error in the supply line of the system. Even a minor leakage in the supply line can lead to significant water loss every day.

“Nuts” in the line are to blame. If the nuts are loose or worn out, leakage is the ultimate result. Please tighten the nuts or replace them if broken or worn out to sort out the problem.

Faulty vertical float

The job of the vertical float in a toilet tank is to regulate the water flow. If it is broken or damaged, the water flow regulation will be interrupted. Therefore, the toilet tank will overflow and lose water even when you have yet to begin flushing.

In outdated toilet tanks, a vertical float will not be present. Instead, you will find the ballcock, which does the same job as a vertical float.

If you have a ballcock in your toilet tank, please check its functionality to ensure it is the culprit.

In case they are the cause, please replace them.

Where can you locate the ballcock or the vertical float in your tank? They are found in the shaft of the fill valve. (Thank us later)

Damaged flapper

Another common cause for toilet tanks to lose water is a damaged or worn-out flapper.

Is the flapper an important part of the toilet tank? How does it affect the water flow and result in water loss?

Flappers are another vital part of the water regulation system in toilet tanks. Their job is to allow and deny water flow as needed by opening and closing.

When you flush your toilet, the flapper will open within the tank and let water flow into the tank. When the flushing is done, it will close itself and disrupt water from flowing further, and starts to refill the tank.

Now think – what would happen if the flapper had tears and leakages? Or if the flapper is worn out and not in good condition?

Exactly, they will not perform well – which is to say, the water regulation will not run properly. So water will leak and keep losing water out of the tank. Replace the flapper to get back to regular operation.

Loose or worn-out tank bolts

Tank bolts can be the secret culprits behind water loss in toilet tanks, even though they seem innocent.

If the tank bolts are worn out or lose by any chance, water will find its way through them and keep leaking into the bowl. And surprise!! You have a high water bill every month.

Check the bolts and tighten them properly. If the washers are worn out, replace the bolts with new ones.

Cracks in the tank or bowl

The worst possible cause cracks in the toilet’s tank or bowl.

New toilets are not prone to this issue, but if your toilet has had a long life, then it is highly likely.

Cracks in the tank or the bowl can lead to significant water loss. And there is no way around to fix it unless you replace it with a new one.

Signs of a Toilet Tank Losing Water

So you are getting unusually high water bills and suspecting a water leakage? Maybe from the toilet? But you do not know for sure?

Let us help you out.

If you suspect a water loss or leakage from your toilet tank but are unsure of it, a few signs will help confirm the issue.

You can also run an easy and magical test to reconfirm and finalize the decision.

Let’s get to all of them.

Below are signs of a toilet tank losing water,

The toilet will flush on its own without you having anything to do with the handle ( no, you do not have a ghost in your house, it’s the malfunction)
Even after minutes of flushing, you will be able to notice water flowing smoothly around the corners of the bowl.
Are you taking on a hassle to press down or jiggle your handle to get the bowl and tank to work correctly? It might be a sign.
Have you ever heard sounds from the toilet as if someone is using it, but to your surprise, there is nobody? No, it is not a bizarre and spooky incident. Your toilet tank must be having a water loss issue.

If you did check off any of the above signs, you need to go one step further to confirm the availability of the problem 100%. You can do a straightforward test for this purpose.

Take some food coloring from the kitchen and put a few drops in the toilet tank. Do not use or flush the toilet for 10 to 15 minutes. Inspect the toilet bowls afterward for any signs of colored water to confirm if water leaks from the tank.