Lead was historically used in Roman plumbing and gives the word “plumber” its root. The Latin word for lead was plumbum, which produced the English words plumbing and plumber.
Roman builders used lead for water pipes, fittings, roof coverings, weights, and other purposes because it is soft, easy to cast, and resistant to some forms of corrosion. Lead pipes could be shaped and joined more easily than many alternatives available in antiquity.
The historical use of lead does not mean Roman water systems were uniformly unsafe or that every illness in Rome was caused by lead. Water chemistry, pipe age, household practices, and exposure routes all affected risk. Modern health science clearly recognizes lead as toxic, particularly for children, and many countries restrict its use in drinking-water systems.
Copper, iron, and bronze were also important Roman materials, but they do not explain the linguistic origin of plumber. The word’s connection is specifically to plumbum, the Latin name for lead.