As we know, a typical toilet is a plumbing fixture which collects human wastes and removes them through pipes into a sewer system. A standard toilet includes a bowl and a tank, both of them are filled with water. The tank holds the water used to flush the waste out of the bowl. While the bowl is not only a receptacle for waste, but also helps to keep sewer gases from entering the room through the trap. How to choose a toilet? Until recently, the decision was still based primarily on their styles. From the looking, we know that there wasn't much difference from one toilet to another. Toilets not only looked similar, but also worked with the same functionality, and their mechanical designs had not changed much since the 1800’s.