Plumbing originated during ancient civilizations such as the Greek, Roman, Persian, Indian, and Chinese cities as they developed public baths and needed to provide potable water and wastewater removal, for larger numbers of people. Standardized earthen plumbing pipes with broad flanges making use of asphalt for preventing leakages appeared in the urban settlements of the Indus Valley Civilization by 2700 BC. The Romans used lead pipe inscriptions to prevent water theft. 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.
When a person has a blockage in their sewage system they often try to fix it themselves by adding an acid or a base such as Drano in an attempt to dissolve or dislodge the problem. These chemicals can get into the plumbers eyes when the sewage is splashed during the repair. The plumbers skin during the repair does come into contact with the sewage water. The owner of the toilet might not report to the plumber they have already tried Drano a highly caustic base .