A flush toilet (also known as a flushing toilet, flush lavatory or water closet (WC)) is a toilet that disposes of human excreta (urine and feces) by using water to flush it through a drainpipe to another location for disposal, thus maintaining a separation between humans and their excreta.
Flush toilets can be designed for sitting (in which case they are also called "Western" toilets) or for squatting, in the case of squat toilets.
The siphon action quickly (4–7 seconds) “pulls” nearly all of the water and waste in the bowl and the on-rushing tank water down the drain—it flushes.
Flush toilets usually incorporate an "S", "U", "J", or "P" shaped bend (called a trap, such as P trap or S trap) that causes the water in the toilet bowl to collect and act as a seal against sewer gases (trapping the gases).
The focus of this article is a flush toilet that uses a mechanical flush from a water cistern that is above the toilet.
A typical flush toilet is a vitreous, ceramic bowl containing water, plus plumbing to rapidly fill it with more water.
This rapid influx from the tank causes the swirling water in the bowl to rapidly rise and fill the U-shaped inverted siphon tube mounted in the back of the toilet.
This full siphon tube starts the toilet's siphonic action.
The water in the toilet bowl is connected to a hollow drain pipe shaped like an upside-down U connecting the drain.