The Ultimate Guide to Toilet Replacement

Is it time to update your old toilet? Sick of wasting water, high water bills and an ugly bathroom? Whether it is a leaking toilet, discoloured toilet, broken toilet, your toilet is wasting water or just time for something new, this guide will help you to do two things really well; 1. Look like a bloody legend who knows what they are talking about in front of your plumber and 2. Help you to understand your options when shopping for a new toilet.

Understanding the components of a toilet.

First you need to know that every toilet has 2 main components — the cistern (or water tank) and the pan (that you sit on). The cistern holds enough water so that when you release the water, it will flush away what is inside the pan. Cisterns are always connected to the pan but the connection can vary from toilet to toilet.

Styles of toilets.

Behind the wall or Concealed cisterns:

When the cistern site behind a wall and the pan sits in front of the wall. Concealed cisterns are great to create visual space in tight spaces as well as creating a shelf in the bathroom which can be a great option for storage. This is an option for a bathroom renovation or for people building new homes but not a simple replacement option.

Cistern lives behind Chrome plate above toilet. Pipe goes from bottom of cistern, through tiles and into back of the pan.


Close coupled Cistern:

When the cistern and the pan are bolted together and both are in front of wall. Water flows from the cistern directly into pan without an extra pipe.

Close coupled toilet.


Close coupled back to wall:

When the pan goes completely back to the wall. Very popular option, looks great and can make a tired bathroom look new again. Here is a picture that one of our inner west plumbers installed a few weeks ago that turned out great!

BEFORE on left: Linked toilet. AFTER on right: Back to wall close coupled toilet. No need to change any pipework/make a big mess — just a straight swap over.


Linked / connector suite:

When the cistern and the pan are seperado and they are joined by a pipe that is sometimes covered (picture below) and sometimes not (picture above). Not the prettiest look but it can be overcome. Plastic cisterns can discolour over time and can make your bathroom look cheap. These can be replaced by close coupled pans and back to wall close coupled pans but if you are on a budget, consider just changing the cistern! Changing the cistern (and toilet seat) can still brighten up your bathroom. Here is an example that Sandy, our Marrickville plumber, completed not long ago.

BEFORE: Discoloured plastic cistern and toilet seat. AFTER: new ceramic cistern and new plastic seat.


Water usage:

Look out for the WELS rating on your new toilet. Older toilets can flush up to 13 litres per flush! You can cut this down to 3 litres with a water efficient toilet. Not only good for the environment but also good for your wallet!

Where does the water come in and where does the water go out?

It important to understand where your water is fed from and where it goes as this will determine the type of toilet you can use.

Where does the water come from?

With most toilets the water is fed from the bottom of the cistern (bottom inlet) or from behind the wall and inside the cistern (back inlet). Back inlets exist so that you don’t see the water pipe enter the toilet. They look great but make it hard to swap toilets without moving the pipe behind the wall. Bottom inlets are great because they open up the options you have for replacing a toilet without having to move pipes.

Bottom inlet on LHS and back inlet on RHS.


Where does the water go?

Toilets can be either a P trap or S trap. This mean the water either leaves the pan through the floor (S-trap) or through the wall (P-trap). It is crucial to get this right!

How to measure: Info for the plumber and the person selling you the toilet.

To help the person selling you the toilet 2 key bits of info are required. You guessed it: Where does the water come in and where does the water go out?

For the inlet: Mark an imaginary line from the centre of the toilet and measure to the centre of the tap (x). Then measure from the ground up to the centre of the tap (y).

For the outlet: P-Trap — Measure either off the floor to centre of pipe (X) or S-trap – from the wall to the centre of the pipe (Y).


Things to consider:

  1. What set up do you currently have?
  2. Where are the inlet and outlet? (measurements in millimetres)
  3. What style of toilet do you want?
  4. How much water will it use?

When you have clarity over these things, it’s time to call your plumber and make your bathroom look great again. Doing this will lower your water bill, reduce your footprint on the earth + add value to your home — It’s a no brainer. Good luck with your renovation!