^ Jump up to: a b Joseph O. Falkinham III; Elizabeth D. Hilborn; Matthew J. Arduino; Amy Pruden; Marc A. Edwards (August 2015). "Epidemiology and Ecology of Opportunistic Premises Plumbing Pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa". Environ Health Perspectives;. 123 (8). doi:10.1289/ehp.1408692. Archived from the original on May 31, 2015. Retrieved August 1, 2015.
The word "plumber" dates from the Roman Empire. The Latin for lead is plumbum. 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.