In plumbing, the term ‘waste’ refers to the tube which is fixed at the base of a sink, basin or sanitary device (such as toilet or bidet). This tube is made of metal and allows waste water to run through it, via a trap, and then into a drain, while also acting as a barrier to possible blockages.
The top of the waste is called the shoulder or flange and this is the metal part you see in the plughole, the finish on the flange will usually match the finish on the taps of the basin.
Wastes are made to standard sizes in order to fit any basin waste hole and usually come supplied with a specific type of plug, stopper or grill. Bathroom sinks usually have a waste diameter of 32mm (1.25″) while baths, showers and kitchen sinks will usually be 40mm (1.5″).
There are a number of different types of waste available for sinks and basins, the pop up waste is just one type.
A pop-up waste, or pop up assembly, refers to the type of pipe fitting that joins a sink, basin or bidet to a waste pipe at the plughole. They incorporate a plug or stopper which is operated with a control. You may also find pop-up wastes in other sanitary appliances.
The control on the pop up waste is usually a lever you pull or a knob you turn. It is often found behind or on the tap fixture, or it may be attached to the overflow which is usually below the tap, in the basin. To operate the pop-up stopper, the lever is pulled up to close the plug and pushed down to open it, or the knob is turned one way to open and the other to close.
Other waste systems
Plug and chain wastes are a traditional style of waste with a plug connected to a chain that can be used to block the plug hole.
Clicker wastes have a stopper that is operated by pushing it. You push once to close it and push again to open it, and so it does not have a separate control like the pop-up waste. This waste can also be referred to as the push button waste, click-clack waste or sprung plug.
Flip top wastes have a simple design has a disc-shaped stopper that can be rotated to open or close the plug hole.
Captive wastes have a plug that sits on a bar and remains in the plughole. It is pulled up to open or pushed down to close. This type of waste is fairly common in public bathrooms as the plug cannot be removed.
Basket strainer wastes are common in kitchen sinks as it has a strainer which will prevent food and other waste from blocking the drain of the sink by collecting it before it can pass through the waste. The basket stopper in this waste can be operated in a similar way to the pop-up waste, with a control to lift and lower it, or it can simply be pulled in and out.
Flush grated wastes are common in showers or sinks where the waste water needs to continuously flow away, as these wastes do not fit a plug or stopper.
Slotted wastes or unslotted wastes?
Most wastes will be available in both slotted and unslotted forms. The type of waste you need will depend on whether the basin has an overflow built-in it or not. The overflow of a sink assists with drainage as it allows air into the drain when the sink is full. A sink without an overflow will act like a vacuum when full and will drain slower, therefore if you do have a built in overflow it is a good idea to ensure it is working correctly. Most sinks will have a built-in overflow; these will require slotted wastes. This is so that when the water passes through the overflow it can flow through the holes into the drain. It is important to ensure the slots of the waste line up with the overflow so the water can run efficiently. Unslotted wastes do not have any holes and should only be installed into systems without an overflow.