A basin waste is a fitting that attaches to the outlet of a wash basin and allows for the outlet to be closed to keep water in the basin and opened to drain it. Basin waste fittings range in complexity from simple variants which are opened and closed by a loose plug to sophisticated, pop-up models. All types may be fitted with integral ports or slots allowing for use in basins with or without overflows.
Basin waste fittings are the parts of any wash basin which allow water to be trapped for use and released to drain out. They also serve as a connection point for the waste trap and waste water pipe system. These fittings are connected at the bottom of the basin and are typically flush with the inside surface with a protruding, threaded stub on the outside of the basin to connect the waste water pipe system. A basin waste is basically a hollow tube with a shoulder machined into the end which is located inside the basin. This shoulder allows a removable plug or pop-up mechanism to seat snugly forming a water tight seal.
The two main categories of basin waste fittings are usually differentiated by the type of plug system. The most simple of these close using a loose, close fitting plastic or rubber plug typically secured to the basin by a decorative bead chain. The other basin waste plug system is the integral, pop-up plug type. These fittings have a built-in plug that is usually depressed to lock in place in a sealing position. To drain the basin, the plug is depressed again, thereby unlocking it and causing it to “pop up” to open the waste channel.
Other, more sophisticated systems feature matching pop-up basin waste and faucet sets which feature a separate control button or lever located on the faucet set which opens the plug. Both pop-up and the more simple loose plug basin wastes may feature a set of ports or slots cut into the throat of the fitting depending on whether or not the basin has an overflow system. This is an important point to consider when buying a fitting as they are generally not interchangeable.
Most basin waste fittings are made with chrome plated brass bodies and, in the case of pop-up fittings, stainless steel moving parts. The lower end of the fitting which protrudes through the bottom of the basin is fitted with a thread which allows it to be locked into place with a special nut and washer. This threaded stub also affords a connection point for the waste trap and waste water piping.