(Wikipedia/Angie) Modern tap mechanism. Tap photo by Angie of Sawara, Chiba-ken, Japan.
Who invented the water faucet?
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JANUARY 03, 2008
April Holladay, HappyNews Citizen Journalist

Q: Who invented the water faucet?
"Zipper," Buffalo, NY
A: That simple machine we take for granted is a valve, whose origins goes back into prehistory. Perhaps a clever human decided to control the flow of a stream or river by blocking its flow with large stones or a tree trunk and thus hit upon the notion.
However the idea sprang into being, it ranks with the invention of the wheel. People could now regulate water flow. Early Egyptians and Greeks devised valves to divert water for drinking and crop irrigation. The Romans advanced these ideas enough to deliver water to individual buildings. Their plumbing had plug valves (stopcocks) and check valves to prevent backflow.
A plug valve is a conical plug with a hole. By turning the plug the hole is either lined up with the pipe so water flows or set at right angles to block flow.
In the early 1500s, Leonardo da Vinci designed canals and irrigation projects that used valves. He left sketches illustrating his ideas. In 1705, Thomas Newcomen invented the first industrial steam engine. That generated new interest in valves since Newcomen needed better valves to contain high steam pressures built up in his engines. In February 1870, J.H. Davis filed a patent on a globe valve — the familiar faucet with the round handle. Soon after, in April of that year, F. Manz filed a patent for a beer faucet.
(Answered Oct. 11, 2002; updated Dec. 4, 2007)