Toilet Waste Pipe Leaking And How To Fix it?

Having your toilet waste pipe leaking is not usually noticed so easily. However, you might occasionally notice sewer smells or the bathroom floor seems to be rising.

This problem can quickly affect surrounding areas and cause rotting or damaged floors, walls, and surrounding fixtures.

If not fixed on time, this problem can require more steps than just replacing a toilet wax ring. Not to mention the inconvenience of having toilet waste overflowing your bathroom.

You want your toilet base sitting correctly on the bathroom floor to avoid any possible problems.

We gathered crucial information for anyone looking to repair a leaking toilet base for this to be possible. So please stick with us as we show you the WHY’s and HOW’s of toilet leak repairs.

Toilet Waste Pipe Leaking When I Flush


Before we get into fixing the toilet leak problem, we have to pinpoint the cause of your exact situation.

Noticing a leak after flushing may or may not mean that you’re dealing with a toilet waste pipe leaking. Other toilet parts may cause a leak due to malfunctioning, so it’s crucial to locate the leak first.

If you notice a leak when you flush a toilet, chances are you are dealing with one of these problems:

  • A leak from the toilet tank
  • A constant running water
  • A leak between a toilet tank and a toilet bowl
  • A leak from the toilet base

As you can notice, a leak from flushing can come from different places surrounding the toilet. Each of these situations possibly also has another cause that triggered a leak.

For example, a leak from the toilet tank itself may be indicating a problem with your toilet tank parts. If some toilet tank parts stop working correctly, they may cause a toilet tank to leak.

What usually influences the constant running water is the toilet tank part called a toilet flapper. A toilet flapper sits at the base of the tank and controls the running of the water down the toilet.

If that seems to be the problem, know this is easily fixable. All you need to do is pick a suitable toilet flapper to replace the faulty one.

A leak between a toilet tank and the toilet bowl can also indicate various causes, typically linked to the tank. [1]

Finally, a leak at the toilet base is what this article is centered about. A leak of this type can be caused by several different reasons – so let’s take a look at what those might be!

What Caused a Toilet Leak?


A leak at the toilet base indicates that some of the materials started deteriorating. In some other cases, it can mean that the toilet is improperly installed in the first place.

  • Rusted bolts at the base of the toilet can make the toilet base shift
  • A deteriorated wax ring can cause water to leak out
  • Improperly put or deteriorated caulking can also cause toilet base leaks

A toilet leak caused by these materials deteriorating can simply be solved by replacing the faulty parts with new ones.

If your toilet base is installed just recently and you doubt these causes, you may be experiencing condensation.

Due to the temperature difference in the toilet tank and a shower, water droplets may appear on the outside of the toilet.

These can create a puddle at the base of your toilet and make you think your toilet is leaking. The best way to cope with this is to figure out how to stop the condensation in your bathroom. [2]

Another thing that may be the cause is the improperly installed toilet. To make your new toilet fit perfectly, you want to make sure you get proper measurements, also called toilet rough-in measurements.

What this type of measurement reminds us of is that the way of installing a toilet largely depends on the type of toilet you have.

How To Test For a Toilet Waste Pipe Leaking


In most cases, you won’t be sure if your toilet waste pipe is leaking or if there’s something else causing the problem.

The toilet base replacement requires new materials and time on your hands, so you want to make sure it’s what needs replacement.

To do this, you need to test for a toilet waste pipe leaking. Doing this is very simple, and all you need to do is follow these steps:

  • Make sure the toilet tank is filled with water
  • Flush the toilet
  • Check if the water is coming out of the base during flushing
  • If not sure, you can add food dye to the flushed water so you can trace it more easily
  • Check if there’s water left at the base of the toilet after the flushing is over

Water leaking out of the base is a clear indicator you have a toilet waste pipe leaking problem.

Water not staying at the base of the toilet creating a P-trap is also a common indicator of this problem. Without this water, sewer gasses can enter your home, and these can be harmful to your health. [3]

Noticing foul smells coming from your bathroom is, therefore, another common indicator.

Another clear indicator of a toilet base pipe leaking is floor damage. Floor damage can be traced by foul smells, tiles rising up, puddles of water, and mold.

Mold develops easily in humid places with still water, and this can pose many health risks. [4]

Make sure to locate and fix a leak under a bathroom floor in order to fix this immediately.

How To Stop Toilet Waste Pipe Leaking 


Some very mild leaking can be caused by cracks in the toilet bowl. Make sure to check for those before you start the process of fixing the toilet waste pipe.

Apart from that, usually replacing the seal and properly reinstalling the toilet fixes this problem.

You won’t know if your toilet gasket is the problem if you don’t remove the toilet first. Since the process of replacing the toilet is for some more advanced, they tend to call the professionals.

However, this process is fairly simple, and all you need to do is follow a few steps. Apart from the repair kit of your choice, you’re going to need:

  • Gloves
  • Something to mop the floor
  • New toilet bolts
  • New toilet seal (and sometimes caulking)
  • A pencil for measurements
  • New toilet bowl (if this one has cracks in it)

The first thing you’ll need to do is to turn off the main water valve. Then flush the toilet to empty the toilet tank completely.

Depending on the type of toilet you have, your next step is most likely loosening the bots on the flushing pipe. This will allow you to remove the toilet tank.

Be careful when you do this, as sometimes excess water can spill out the tank or the pipe.

The next step will require you to remove the flush pipe and unscrew the toilet bowl bolts. After that, you should be able to lift the toilet bowl (make sure to ask a friend for help when doing this).

Your next step is replacing a toilet seal, so let’s take a look at the best ways to do so.

How To Seal a Leaking Toilet Waste Pipe


Possibly the trickiest part of this process is removing the toilet flange. Once you’ve separated the toilet, it’s time to clean the old putty by using a putty knife.

Make sure to use rubber gloves and constantly keep the area clean with a cleaning cloth. This is especially important since the toilet wax can be sticky and sometimes very tricky to clean once it’s stuck to a surface.

The next step is to choose the proper toilet seal for your toilet. Depending on the type of the toilet and also your personal choice, you may opt for either a wax or a waxless toilet seal.

These are installed differently. Our recommendation is for you to choose the one you think matches your skillset.

After you place a toilet seal, the next step is putting the toilet bowl back on. This will most likely require a helping hand.

After this, all you need to do is trace the same process, only backward. Screw in the bolts, a toilet flush pipe, and the toilet tank accordingly.

Make sure to tighten the bolts, so the toilet doesn’t shift. Then, turn on the water again and wait for your toilet tank to fill up.

This process will be enough for most of the toilet leaks at the base. Now, let’s take a look at what you can do if the problem still resides.

Toilet Waste Pipe Leaking Outside

The previous process only helps when you notice a leak at the toilet base.

However, if your bathroom floor is rising up, chances are there’s a burst pipe underneath the floor. This will require a more complicated process of removing the flooring and repairing the pipe.

We recommend calling professionals for this job as this is not a simple DIY task.

The same thing goes for a waste pipe leaking outside of your house. If you notice a spike of green color in your yard, chances are there’s a pipe burst happening right there.

Sewage acts as a fertilizer for the plants and is therefore good for them. [5]

However, if your yard is overly damp, it might be the case of a burst sewage pipe or a full septic tank.

Some other symptoms of a sewer pipe leaking outside your home are:

  • Foundation cracks
  • Slow draining
  • Pooling or wet yard
  • Sewer gas smells in your yard and/or bathroom

Not fixing this problem can invite rats and other pests to your home. There are also other inconveniences of slow draining water and awful smells around your home.

Fixing the sewer waste pipe leak requires a more complex repair process that is outside the scope of this article. It will most likely require you to phone professional plumbers and/or technicians for this job.

This is especially because they have the advanced equipment for this job that most homeowners simply don’t have.

The Bottom Line

 Most of the toilet waste pipe leaking problems can be solved by replacing the toilet wax at the base of the toilet.

This is because most of these leakages are due to the material of the seal deteriorating over time. The same goes for the loosened bolts or caulking at the toilet base.

However, sometimes a toilet isn’t properly installed at all. This is then a problem of improper measurement in the first place, and your toilet needs to be reinstalled.

If you notice a leak beneath the bathroom floor or outside your home, this indicates a burst sewer pipe. Most often, this requires professional technicians who will replace the burst pipe with the use of special equipment.