Bath waste system buying guide

Bath waste system buying guide

Jeremy, construction site supervisor, Cardiff

Guide written by:

Jeremy, construction site supervisor, Cardiff

134 guides

A bath waste provides drainage between the bathtub and the drainage system. Made up of a waste plug, waste trap, washers and connected to a PVC pipe, a bath waste also has a plug, which can be a plug and chain, a click clack plug or a pop up plug. An overflow is also included to prevent overflowing.

Important features

  • Diameter
  • Overflow
  • Waste plug
  • Sealing type
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When using your bathtub, you should be able to shower in the same way that you would take a bath. Firstly, the waste system must allow the water to drain away quickly as it flows from the shower head, and secondly, ensure a watertight seal for the bathtub to fill up.

Also, if you forget to turn off the water when preparing your bath, the waste system should also be equipped with an overflow to avoid flooding your home. A good waste system should fill all of these functions.

Parts of a bath waste system

Waste plug

The waste plug is the visible element at the bottom of the bathtub. The waste plug connects the bathtub with the waste trap (placed underneath). In most cases it is installed by screwing it in. The waste plug is attached to a washer.


The waste trap has two functions: the first is to trap materials and waste that might fall into the bathtub, preventing them from going down the pipes. The second is to prevent bad odours from the pipes rising up into the bathroom with a trap seal.


This is often a pop up system which plugs or unplugs the waste plug and therefore enables you to fill or empty the bathtub. This is controlled by a knob or a pull cord and is operated by a cable or linkage. There are also manual plugs (rubber plugs and a chain) and click clack plugs that you press with your feet.


This is a safety drain in case you forget to turn off the water at the right time, therefore preventing flooding. The overflow is connected to the waste trap, often with a flexible hose.

Bathtubs come in a variety of shapes, materials and volumes. However, they all have so-called "standard" sizes in terms of drainage, the position of the overflow and the length of the sealing system. The sizes are as follows:

  • vertical distance between waste plug and overflow = 400 mm;
  • horizontal distance between waste plug and overflow = 200 mm;
  • overflow pipe length = from 54 to 130 cm;
  • waste trap with trap seal greater than or equal to 50 mm.

When choosing your waste system, make sure that the model you have chosen is standard or universal.

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There are different types of bath waste systems for all functions. They are made of at least one waste plug, waste trap and overflow pipe. The difference between the models is in the plug mechanism:

  • the conventional system consists of a cable connected to a lever on the waste plug which opens or closes. This cable is connected to a knob or pull cord at the other end;
  • the click clack plug is a self-closing system which opens or closes the waste plug by applying pressure with your feet;
  • the manual system seals with a rubber plug fitted with a metal chain.

Make your decision based on whether your bathtub has a stopper. However, you can choose an automatic waste system even if your bathtub has a knob.

If your bathtub has standard dimensions, then the different centre-to-centre distances shouldn't be a problem as they are all the same. Nevertheless, be aware of the following features.

Waste system characteristics

Bathtub drainage diameter

  • 90 mm
  • 60 mm
  • 50 mm

The 2 types of overflow 

Conventional overflow: you will need a waste system that includes a pipe to be connected to the overflow on one side, and to the waste trap on the other side. Integrated overflow: some bathtubs have a concealed overflow pipe that runs directly next to the main drain hole.

Sealing system

  • Manual plug, with plug and chain.
  • Control plug, with a knob or pull cord.
  • Automatic plug.

Ground clearance

This is very important as it determines the space available between the bottom of the bathtub and the floor. This may or may not force you to purchase an ultra-flat waste system. As a general rule, the minimum recommended space is 13 cm.

Drainage diameter

Again this setting is standardised. Bathtub drainage is made of 40 mm PVC. Moreover, the majority of waste systems available on the market offer a 40 mm output.

A blockage may occur at any time. Whether this is because of waste, hair or an object that goes down the waste plug. It may also be because the system isn't flowing correctly. For this reason, standards require access to the drainage system through an access panel. This panel must be located at the horizontal level of the waste trap, therefore making maintenance and dismantling easier. There a number of access panels in different sizes. It is important to choose an access panel that can be locked to prevent risks.

More information 

Explore our advice guides related to the bathroom:

Explore the ManoMano catalog
Access Panels

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Guide written by:

Jeremy, construction site supervisor, Cardiff, 134 guides

Jeremy, construction site supervisor, Cardiff

Electrician by trade, I first worked in industrial estates where I installed, wired and fixed a large number of electrical installations. After this, I managed a team of electricians for this type of work. 10 years or so ago, I turned to building and construction. From the modest family home, to gyms and theatres; I have been able to coordinate, audit and organise all sorts of construction sites. for 4 years now, I am restaoring and bulding an extrension to a bungalow in the heart of the welsh countyside. My experience in manual work and my knowledge means I am proud to be of service. Terraces, interior design, roofing, plumbing, electricty, anything goes! We have, my wife, daughter and I, built almost everything we have from scratch! So to answer all of your questions, and to orientate and advise you on coosing your tools? Easy!

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