Toilets are a necessity in our culture. From their invention, to their growth in popularity in the 1920's, toilets have greatly evolved into the fixtures we use today. While they are a relatively simple apparatus, many improvements have been made through the years.

There are many types of toilets in use today. They differ based on customs and traditional use. The most commonly used toilet in the West, where the sitting position is preferred, is the flush toilet. Century’s worth of development led to the flush toilet. Today's most popular models consist of a water tank attached to the seat. When the apparatus is flushed, the water in the tank is evacuated into the bowl, using pressure and gravity to remove the contents down the drain. When the water in the tank is empty, it begins to fill again. This is stopped by a mechanism that usually involves a lever attached to a flotation device. Once the water reaches a certain level, the water is automatically shut off.