How To Fix A Leaking Toilet (Causes and Solutions)

by Dan | Last Updated: January 15, 2021
A leaking toilet can be a water hog. The Environmental Protection Agency estimates that the average family loses up to 180 gallons of water per week from household leaks. Of these, the toilet is the worst known culprit and could contribute close to 50% of the water wasted.

Even with a new High Efficient Toilet that uses 1.28 GPF, you may be wasting water without your knowledge. Sure. We’ve had homeowners lament that their supposedly water efficient systems used way too much water than their old toilets. The cause was, of course, water dripping from their toilet.

Since you are reading this, it’s very likely that you have the same problem. So, let us show you how to fix a leaking toilet.

Common Causes Of Toilet Leaks And How To Fix Them

1. Leaks From The Tank

The toilet cistern is the major culprit in toilet leaks and loses water in 3 ways:

  • Visible-leaks: where the water leaks or spills over and floods on the nearby floor
  • Invisible cracks in the walls
  • Secret-leaks: where the water leaks directly into the bowl


Visible Leaks And Spill-Overs

If your toilet tank is overflowing (water dripping from the brim), the chances are that the float and the inlet valve system is not working correctly and needs readjustment. Also known as the ball, the toilet float is a water-fill regulating device that switches the inlet valve ON and OFF.

In case the mechanism is faulty, the level water will rise and spill through the overflow tube to the bowl, and later spill over the brim to your floors.

How To Fix A Leaking Toilet

  1. Remove the lid of the tank and place it aside. Handle it with care. Toilets such as TOTO MS604114CEFG-01 Ultramax II have ceramic lids that may crack easily when mishandled.
  2. Locate and inspect the ball. If the tank is full, the float should be floating on top of the water. When the cistern is empty, the float falls to the bottom of the tank.
    If the cistern is full, but the float is at the bottom, it’s likely that it is worn out and requires replacement. If the float is at the top, but the water is still running, this means that it is sitting too high and needs to be adjusted.
  3. Locate an adjusting screw where the float rod connects to the valve and turn it clockwise. This should lower the ball and the water level.
    You could use a screwdriver for this. If you don’t have one, simply use your hands to bend the rod downwards.


Invisible Cracks

Do know that your tank could also leak from fine cracks in the walls. Most homeowners confuse this with a sweating tank.

Best Way To Diagnose Invisible Cracks

  1. Add 6-7 drops of food color to the water in the cistern
  2. After around 20 minutes, the colored water from the tank should be visible on the outside of the container.

What’s The Remedy For This?


Secret Leaks

As I told you, if your toilet tank won’t fill,  you may be having a leaking toilet without knowing. This happens when the water leaks through the flapper into the bowl. This is the most dangerous type of leak since it’s hard to detect.

If a toilet is leaking from the flapper, the chances are that the flapper (also known as the valve seal) is not sitting properly over the drainage hole or it’s worn out and requires requirement.

You can try to fix this by repositioning the flapper or replacing it altogether.
Our other article on how to replace a flapper is the ultimate guide on how to diagnose a leaking flapper and how to fix it.

2. Leaking From The Base

If the floor around your toilet base feels spongy or there is a small pool of water around it, the chances are that there is a leak at the flange.

Also known as a closet/toilet flange, this is a pipe fitting that connects the commode’s drain pipe to your drainage system. It also mounts and holds the entire fixture firmly on the floor.

The closet flange uses a wax ring to prevent leaks. However, the ring develops leaks over time, and, therefore, requires replacement. This isn’t an easy task, but any enthusiastic DIYer can breeze through it.


Our guide on how to install a toilet flange and how to remove toilet flange has everything you need to stop leaks from the base.

You might also find this video quite helpful:


Fixing the most common causes of leaks can be done without involving your local plumber. It’s also easier and cheaper than most homeowners think. You only need the right tools and a little know-how. Other than this guide, there are hundreds of helpful how-to videos on YouTube that you can make good use of as well.

Lastly, remember that learning how to fix a leaking toilet won’t be of much use if what you actually need is a new toilet. If your system requires maintenance every other weekend, I guess it’s time you pulled the trigger and bought yourself a new toilet. If this is the case, our best toilet buying guide might be the best place to start your search.

Dan is the editor in chief and founder of this site, after running into troubles with his own old toilet a while ago. Discussing toilets is not your everyday topic, so let’s talk toilets today.