How to Fix a Toilet Leaking at the Base

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A toilet leaking at the base can only mean this: things are about to get dirty. 

You’ll need to react quickly to prevent further damage and save your bathroom from flooding. It shouldn’t be a big issue, but you still need to spend a couple of hours stopping the leakage.

The first thing you must do is pinpoint the problem because it determines the solution. After that, it’s all about rolling up your sleeves and replacing a few elements.

In this post, we’ll go through the causes of toilet leaks and how to fix them. 

What Causes The Toilet Base to Leak?

Toilet base leaks can have one of the following causes:

1. The Toilet Base Has Cracked

Toilet base cracks are the most common reason why a toilet base starts leaking, and they are also the easiest to repair. The crack may appear to be only a hairline fissure, but it can cause your toilet to leak water at a constant rate.

Replacing a cracked toilet base takes only a few minutes. There are three types of toilet bases you can look for: the round bowl with a round base, an elongated bowl with a round base, and an elongated bowl with a standard oval base.

2. Tee Bolts Are Loose

Tee bolts function as a clip that holds the toilet base in place. Find these tee bolts at the back of the bowl, underneath the tank lid. They are secured with nuts which should be tightened up to prevent leakage. 

How do you know that tee bolts are loose? If you can move the base, then it’s not adequately secured.

3. Wax Rings Are Worn Out

The toilet base and wax rings work together to prevent water leakage. If the wax ring is not sealing correctly, it may be worn out. 

Apart from water leakages, a wobbly toilet bowl can sometimes point to a worn-out wax ring. That’s because the bowl sits on top of the wax ring, which gives it additional stability.

A new wax ring is a mixture of natural and synthetic waxes that firmly supports the toilet base and stops the water flow. 

4. Water Condensation Causes Leaks to Damage the Surface

Water condensation occurs when humid air contacts a cold surface and forms dew (water droplets on a chilly surface when damp air is present). 

Since the toilet base is cold, it often causes water condensation. In the case of condensation, the leakage is soft, and it shouldn’t cause significant damage. 

5. The Toilet Is Not Mounted Properly

Another problem may be that the toilet is not properly mounted to the toilet flange. You can see if this is the case by checking if the bowl moves easily. If it does, you need to tighten the bolts holding the bowl in place.

6. The Toilet Tank Lid Is Damaged and Leaking

Damaged tank lids can also cause a leaky base. In this case, you need to look at the tank lid and see if it shows any signs of wear. You will instantly notice the signs, as the cover may contain larger cracks or holes that lets water escape.

7. Damaged Water Supply Tube

You could also be dealing with toilet base water coming from a leak in the supply line pipe. This connects the tank and the bowl.

How to Stop Toilet Base Leakages

Every toilet leaking problem mentioned above has a concrete solution, and the best part is that you can do it on your own.

The most important thing is to twist the shut-off valve and stop the water supply to your toilet. This is next to or beneath the toilet, and you can close it by turning it clockwise. 

It will prevent the toilet from leaking and allow you to work without inconvenience.

Solution 1: Replace the Cracked Toilet Base

First, you need to remove the cracked bowl and replace it with a new one. Try to use the same manufacturer’s model as the original bowl. If it’s not available, you can purchase a bowl with the same dimensions. 

Unscrew the bolts from the cracked toilet base and remove the bowl. Secure the new bowl on top of the existing flange using a new set of screws and bolts.

Solution 2: Tighten the Tee Bolts to Stop Leaking at the Base

Sometimes the toilet is leaking from the tee bolts and their plastic covers. If they are too loose, the solution is to tighten them. 

Look for bolts at the toilet base and twist them clockwise until they don’t go any further. Make sure you don’t overdo it, though, as you might break the bolt.

Solution 3: Replace the Wax Ring

Old wax rings can cause leaking toilet bases, so you should replace them immediately. 

A wax ring connects the toilet bowl with the flange. Remove the old part with a putty knife and make sure no remnants remain. You can also use a wet towel to clean the surface of the flange and the toilet bowl’s underside. 

Apply the sealant to the flange and place the ring on top of it, then fix the bowl over this flange and make sure it’s firmly in its place. The holes on the toilet base must match the holes on the wax ring.

After that, screw the toilet base bolts to make the toilet stable and secure. 

Replacing the wax ring is easy as it doesn’t require any help from an assistant or a professional plumber.

Solution 4: Prevent Water Condensation

Condensation is one of the most frequent causes of toilet base leakages. You can solve this problem by installing bathroom exhaust fans or ventilating fans. This will allow the heated air to escape and prevent condensation from forming on the cold surface of the bowl.

Alternatively, you can insulate your toilet tank more firmly and thoroughly.

Solution 5: Set Up the Toilet Bowl Properly

If the toilet bowl is not properly mounted, it might cause leakage and mess with the toilet drain outlet. To fix this, make sure the bowl is set tightly on top of the flange. When you do so, the toilet bowl should not be able to move back and forth or left and right.

Solution 6: Repair or Replace the Toilet Tank Lid

Damaged or worn-out tank lids can also cause a leaky toilet base. If the problem is not serious, a little tightening might be enough to stop the leaking issue. But if you’re dealing with more significant damage, you need to replace the faulty lid with a new one.

Remove the old one with a putty knife. The new toilet tank lid should be firmly attached to the base and not move freely.

The best toilet tank lids to choose from are molded plastic tank lids, flushometer tank lids, and flapper-less tank lids. We prefer flushometer tank lids as they remain clean for a longer time and don’t easily absorb odors.

Solution 7: Replace the Damaged Supply Line Connection

Old or damaged supply line piping can also cause a leaky toilet base. Toilet pipes get damaged easily, so the best solution is to replace yours with a new one. 

Turn off the water supply valve before doing this. Empty the toilet by flushing it and then unscrew the nuts holding the supply hose. After that, you can set the new hosepipe and put the nuts back.

Tools You’ll Need to Stop the Leak

Before you start doing anything, remember to acquire the right equipment. Here’s what you need:

  • Putty knife to remove the old wax ring and damaged toilet tank
  • Adjustable crescent wrench or pliers to remove old bolts
  • Screwdriver to set the new set of screws
  • Fluidmaster toilet bowl wax ring to replace the existing one
  • Screws and bolts
  • Rubber gloves to prevent contact with the used wax seal and debris
  • Tape to cover the exposed pipe
  • New water supply line, if needed

The Bottom Line

When you notice a toilet base leaking, close the shut-off valve to stop the water from running. It will allow you to inspect the toilet base and pinpoint the problem causing the leakage.

After that, follow the steps described above and you will repair the toilet base in no more than a couple of hours.

Good luck and keep reading Bomisch for more tips on home renovation!


How can you tell if the toilet wax ring is leaking?

Water leaking from the toilet base is one of the telltale indications of a wax ring failing. In this case, you should buy and install a new wax ring.

Why is my toilet leaking through the floor?

A toilet leak usually happens because of a break in the seal between the toilet and the floor. It may be a broken part, like a wax ring or something wrong with the whole toilet.

How do you reseal a toilet to the floor?

To install the toilet, lift it and line up the holes on the base with the tee bolts. Then place it down and use your body weight to make a watertight seal.

Use an adjustable wrench to install new bolts. Replace any washers or nuts that are loose.

Hold the bolt firmly with one hand while you use your other to turn the threaded nuts clockwise — this will tighten the bolts. However, you don’t want to push too hard because the nuts may damage the toilet bowl. 

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