WHY IS MY TOILET LEAKING AT THE BASE?

A leaking toilet may seem like a major cause for concern. However, fear not, the solution is usually much simpler (and more pleasant) than you may expect. In most cases, a couple of tweaks will have everything running like normal. Indeed, understanding a little about how toilets work will help you to take care of your bathroom, and ensure that when leaks do happen, they are a straightforward fix.

This guide explains the causes of toilet leaks, showing steps you can take at home, as well as when it’s time to call in a professional.

WHAT CAUSES A TOILET TO LEAK AT THE BASE?

If you notice water pooling around the base of your toilet, you should first attempt to ascertain precisely where the water is coming from. Water around the base of your toilet does not mean that it is necessarily from a leak, it can be from a multitude of cases.

For example, any of the following can cause water to be present on your bathroom floor:

A spill from a sink, shower, or bath (or someone having tracked water from the bath or shower as they exited)

Water leaking from the wall or ceiling, or any pipe above the spot where the water has pooled

Rain blowing in through an open window

A spilled drink or any other type of liquid spill

So before you assume that the leak is from the toilet, you need to rule out other potential causes, especially before you begin with any home remedies to fix the leak.

BROKEN SEAL OR GASKET

Assuming you are sure that the water comes from the base of the toilet, then the most likely cause is that water is leaking through a broken seal under the toilet. All toilets are fitted with a rubber or wax seal to prevent any of the water from inside leaking out. This is known as the gasket, and it acts as a flange to ensure that the exterior of the toilet remains dry. Over time, these gaskets can perish, which eventually will lead to water leaking out. Although more common in older toilets, it sometimes happens in newer models.

There are other potential causes (for more information, see the section below on ‘What to check if your toilet is leaking’), so don’t assume it’s a flaw in the gasket, although this is by far the most likely cause.

If the problem is not with the wax gasket, then there are two other common causes. These are less common than the failure of the seal, although both are caused by the way that the toilets are constructed.

LOOSE BOLTS

If the problem is definitely not with the seal, it may be with the bolts that connect the toilet to the floor. Toilets are bolted down to the floor of a bathroom with two tee-bolts. These bolts thread up from the mounting ring and pass through holes in the base of the toilet. If these are loose, the toilet bowl can move.

To test this, gently push the base of the toilet; if it moves at all, then the bolts are loose. If there is movement, then it can very easily either break the seal or cause it to fold on itself, leaving space underneath for the water to exit the inner part of the toilet and spill out onto the floor. Every time you flush the toilet after this, drain water can exit the toilet and leak out. Here you can learn about different toilet flushing systems.

CONDENSATION

The final potential cause is simply a matter of physics. If you have a particularly hot or humid bathroom, the relative coolness of the porcelain of the toilet bowl will cause water to condense when it touches it. The water inside the toilet and in the tank helps to keep the porcelain cold. The condensation that takes place on the toilet usually trickles down into the bowl.

However, anything that condenses on the outside of the bowl will eventually trickle down and pool at the base of the toilet. This can give the impression of a leak without any part of the toilet itself actually being broken. Diagnostically, this is an easy problem to spot as you can usually see the beads of water running down the outside of the toilet, particularly if you have just had a hot shower or bath.

WHAT TO CHECK IF YOUR TOILET IS LEAKING

If you do notice your toilet is leaking, then there may be some steps you can take before you call in a professional. The first thing to do is to make some simple checks to ascertain the direct cause as well as to prevent any further leaking.

The following steps should be your first checks:

Dry the leak

This is hopefully the most intuitive one. Place some towels around the base of your toilet to absorb the water. Having standing water in your bathroom is never ideal and, if left unchecked, can cause structural damage and mold.

Check the bolts

Assuming you’ve determined that the cause is not condensation, you can try tightening the bolts connecting the toilet to the floor. First give the toilet a quick waggle – being careful not to push too hard – if there is movement then you should tighten the bolts. Using a putty knife, lift the covers off the bolts. Then using a screwdriver, tighten the bolts until there is no ‘give’ when you try and wiggle the toilet bowl. Once you’ve done that, replace the caps, or the bolts will begin to rust.

Open the windows

Since the cause may be condensation after you take a bath or a shower, you should aim to reduce the humidity in the room to allow the porcelain to dry off. Use the bathroom mirror as a gauge – once the mirror is no longer steamed up, the humidity is low enough. Give it a bit of time once the humidity diminishes, and you’ll be able to see whether the cause was condensation or a leak elsewhere.

AFTER YOU'VE DONE THESE THREE STEPS,

you need to wait. Assuming that the leak is a small pool, rather than water gushing out, you can leave it a day or two to assess whether your quick fixes have worked. If there is still water pooled around the base of the toilet, then it’s time for some more serious repairs. In which case, you’ll need to move onto the next section – ‘How to fix a leaking toilet’.

HOW TO FIX A LEAKING TOILET

Given that dehumidifying the room and tightening the bolts haven’t helped, it may be time to call in a professional. They will most likely replace the wax gasket for you, although if the cause is something more serious, they will need to undertake more advanced work. It is unlikely that an amateur will be able to do the work themselves, and it’s not worth the risk of breaking the toilet and causing a major leak or plumbing problems.

The steps below are the ones a professional plumber will take to fix the toilet:

Turn off the water

The first step is to turn off the toilet water. You can close the water shutoff valve using a wrench or by hand. This prevents water from continuing to flow through the toilet. Once the valve is closed, the toilet will drain. No work should take place until the toilet is fully drained and the plumber is absolutely sure the valve is closed.

Remove toilet

Next, the plumber will remove the toilet from its position by undoing the bolts connecting it to the ground. They will lift the toilet away from its stand and place it on a sheet or blanket.

Remove old gasket

Assuming the problem is the wax gasket, the plumber will need to remove the old wax that is stuck to either the base of the toilet, or the floor. The plumber will be easily able to identify where the leak was coming from by spotting the gap in the gasket.

Add new gasket

The plumber will then add a new wax gasket, using a repair strap to make sure it remains in place as it is tightened in place. Once the wax gasket is in place, it should be properly centered, with both closet bolts in place.

Connect water supply

Then, the plumber will work on the mechanism of the toilet, connecting the water supply tube to the threaded fill-valve shank. Next, they will compress the gasket by pushing down on the toilet bowl rim.

Tighten bolts

Once everything is in place, the plumber will give every bolt and nut a further tightening, before replacing all the cover caps.

Open valve and test

Then, now the toilet is fixed and in place, the plumber will open the valve so that water begins to flow. After a couple of flushes and some observation, it’ll be easy to tell whether the problem is fixed or not.

While a leaking toilet may not seem like a major problem, it very quickly can be. Knowing how to undertake simple steps to maintain your toilet and address common issues will likely save you a lot of problems in the long run.

However, when it comes time to it, calling a professional is almost always the right course of action. After all, a damaged plumbing system is a lot more expensive than hiring a plumber for half a day. So, think of it as an investment – maintain your toilet, and make the call if you can’t fix it. You will not regret it.