How To Fix A Leaking Toilet Waste Pipe Without Removing The Toilet Bowl.

If you have noticed a bad smell coming from your toilet or bathroom and it comes and goes… more than likely its a leaking toilet waste pipe rubber or pan connector rubber known in the trade.

Having a leaking toilet waste pipe really stinks pardon the punt.

Some times when the waste pipe rubber is worn and which is often called toilet pan connector rubber it can leak water when the toilet is flushed and the gases from the main sewer line which is methane back into the room.

Below I will explain on how to test and replace these toilet pan connectors on both a P trap and S trap toilet.

How to test for a leaking toilet waste pipe

Sometimes it’s hard to tell or test if you have a leaking toilet pan connector depending on what toilet trap you have. With a P Trap toilet which is the type that goes through the wall will show up more of a leak from a perished pan connector seal than an S Trap.

P Trap toilet pan test- Make sure that the toilet tank is full for this test.

Get down next to where the toilet pan connector rubber is and push the button on the tank.

Look and feel with your hand for any water escaping from around the seal or if you have any food color die can help to.

Place a couple of drops into the toilet tank doesn’t matter what color it is and then flush the toilet.

If you have a leaking toilet waste pipe rubber it will leak out the colored water.

Make sure to cover your self here by placing a towel under the pan connector so it doesn’t leak all over the floor if there is one there.

S Trap toilet pan test- Make sure the toilet tank is full.

Flush the toilet and check around the black pan connector rubber for any leaks.

As above can add some food color die to help see if there are any leaks but as said above the S Trap is harder to pick up any leaks.

You are relying more on a visual look at the rubber seal to see if any water is leaking out but more to see if the rubber seal is perished and letting methane gases escape back into the room.

Now that we know the difference between a p trap and s trap toilet pan and how to test to see or know if we have a leaking toilet waste pipe.

Below is a step by step procedure on how I do this job and how you should do it and what not to do as well.

You will need some basic hand tools. 

Now I must stress here that this isn’t a 10 min job.

To replace the pan connector rubber seal you will need to remove the toilet pan from its location.

This can be a job in its self as toilets are either screwed and silicon down to the floor or concreted down.

If concreted down then you will have to replace the pan as there non-reusable once they have been concreted down.

These steps are for low, mid and high-level toilets and may vary depending on which toilet suite you have but the principle will all be the same.

Things you will need are

  • Toilet pan connector rubber seal (just ask for it as they’re a standard size)
  • Rubber gloves or surgical gloves to protect our self from diseases
  • Toilet flush pipe seal or pan cone rubber also called (check with old as they come in 40mm and 50mm)
  • Bag of mortar to bed down onto the floor if not and screwing it
  • Pan screws and clear silicon

Step 1 Turn water off- 

Turn the water off at the toilet stop valve to stop water going to the toilet tank cistern. When off push the buttons down on the tank to drain the tank out from all the water.

Step 2 Remove toilet cistern-

  1. Once you have all the water drained out of the tank it’s time to remove the cistern tank. Remove the water inlet pipe to the cistern that connects the cistern to the toilet stop valve you just turned off.
  2. Next loosing off the nut from the flushing pipe. The flushing pipe is that big pipe that sits below the cistern tank and is also connected to the back of the toilet pan. Just let the nut slide down the pipe for now.
  3. Next, remove the screws that hold the cistern onto the wall. There should be a stainless steel screw in each corner of the tank. Remove them and the cistern then should just lift off the flush pipe and from the wall. Just remember there could be a little bit of water left inside the tank so just tip it down the toilet.
  4. Remove the flush pipe from the back of the toilet now and also the toilet flush pipe seal.

Step 3a Remove toilet pan(screwed)-

 Depending on how’s it been installed and brand of the pan.

Some toilet pans are 4 hole screw mounted or 2 holes, either way, they have to be removed.

Depending on the installer they can be star drive or flat drive screws and should be either brass or stainless.

Some installers only silicon down the pans and cut the heads off the screws and silicon them in where the holes are to look like there screwed down so if you are trying to remove a screw and keeps spinning that be what it is then.

  1. Remove the screws from the toilet pan.
  2. Cut the silicon from under the base of the pan with a long-bladed thin knife or hack saw blade.
  3. Once you have cut through most of the silicon and screws removed you might be able to rock the toilet pan side to side breaking away the rest of the silicon.
  4. Once the toilet is fully clear and ready to lift off lean the toilet back towards the wall to drain the excess water that’s inside the trap so you don’t spill it everywhere.

Step 3b Remove toilet pan (concrete)-

  1. When a toilet pan is concreted down to the floor there is only one way to remove. Yep you guessed it smashing it out.
  2. Sometimes they can come out in a couple pieces and other times in millions of pieces.
  3. It will make more of a mess so have an old bucket to place the rubbish into. If you crack the base where the water trap is will leak all over the floor.
  4. Just have a towel or mop handy to clean it up. You may need to chisel any leftover concrete that’s stuck to the floor from under the pan as you want a smooth level surface to work with when installing the new pan. Once it’s all removed and cleaned move to the next step below.

Step 4 Remove the seal-

Once the toilet is removed we can see the pan connector collar.

Remove the white plastic retainer ring and then remove the rubber seal.

Use gloves here if you haven’t already got them on and pull the seal off.

Install the new one and place the retainer ring back on. That is as easy as it is to replace the toilet pan seal rubber.

Step 5 Installing toilet pan-

  1. Make sure the area where you are installing toilet pan is getting silicon and screwed down is dry and clean.
  2. Place the toilet pan back in its location making sure it slides into the new rubber seal all the way. Be careful here as the new rubber will be tight so go easy pushing it through and don’t go too hard slamming it down onto the floor. Remember toilets are porcelain and can break and chip easily.
  3. Once back in position draw a light pencil line around the outside of the toilet base then removes the pan.
  4. Apply a nice bead of silicone making sure staying inside of the pencil lines.
  5. Install the toilet back in place using the pencil line as a guide to where it sits and screw it down. Don’t over tighten the screws or you will crack the pan and up for a new one.
  6. Clean any excess silicon up from around the base and that’s the pan installed.

Step 6 Install toilet cistern-

  1. Remove the old toilet flush pipe cone and slide the new one on. Pull the outside part of the toilet flush pipe seal back on its self and then slide it onto the toilet pan where you removed it beforehand.
  2. Place the toilet cistern onto the flush pipe where the big nut is and start to tighten up the nut. Not to tight yet until we mount the toilet tank.
  3. Mount the toilet tank back onto the wall and screw back then tighten up the flushing pipe nut.
  4. Connect the water supply back to the toilet cistern and turn the water on.
  5. Fill the tank and flush the toilet testing and looking at all joins for any leaks.


That is the simplest and easiest way to repair a leaking toilet waste pipe.

Now you are probably wondering what’s the reason toilet pans get concreted down and not just screwed down and the answer is simple.

Toilets need to be fixed down on a flat and level floor if not it will crack or worse be on a lean.

Nothing worse sitting on a toilet pan and feels like you are falling off it so that’s the main reason why a toilet is concreted down.

Got a leaking pan cone rubber see how to change it today