A plumber is a tradesperson who specializes in installing and maintaining systems used for potable (drinking) water, sewage, and drainage in plumbing systems. The term dates from ancient times, and is related to the Latin word for lead, "plumbum."
The word "plumber" dates from the Roman Empire. In Roman times lead was known as plumbum in Latin (hence the abbreviation of 'Pb' for lead on the periodic table of the elements). Roman roofs used lead in conduits and drain pipes and some were also covered with lead, lead was also used for piping and for making baths. In medieval times anyone who worked with lead was referred to as a plumber as can be seen from an extract of workmen fixing a roof in Westminster Palace and were referred to as plumbers "To Gilbert de Westminster, plumber, working about the roof of the pantry of the little hall, covering it with lead, and about various defects in the roof of the little hall". Thus a person with expertise in working with lead was first known as a Plumbarius which was later shortened to plumber.
The term "White House Plumbers" was a popular name given to the covert White House Special Investigations Unit established on July 24, 1971 during the presidency of Richard Nixon. Their job was to plug intelligence "leaks" in the U.S. Government relating to the Vietnam War (i.e. the Pentagon Papers); hence the term "plumbers".
^EW Wedlake; J Britton (1836). "Westminster Palace". The history of the ancient palace and late Houses of Parliament at Westminster. J B Nichols and son. p. 122. Retrieved 28 June 2010.Cite uses deprecated parameters (help)
^"Doubts raised on US 'plumber Joe'". BBC News. 2008-10-17. Retrieved 2008-10-29. "Joe Wurzelbacher, 34, found himself at the center of a media frenzy on Thursday after "Joe the plumber" was mentioned 26 times during the final debate."