- "… tell Petunia that very funny story about those American plumbers, Mr. Mason. She's been dying to hear…"
- —Vernon Dursley to Mr. Mason, after a dinner party.
A plumber is a Muggle who fixes or puts in piping systems and plumbing fixtures. Mr. Mason had an anecdote about some American plumbers that Petunia Dursley claimed to have been dying to hear, in 1992. Vernon Dursley also told a joke about plumbers to Mr. Mason during a dinner party in 4 Privet Drive, in 1992.
Vladimir Plot was a wizard who ran a plumbing supplies store in Hogsmeade.
Arthur Weasley stated that Muggles repeatedly called in "pumbles" (plumbers) in the hope of repairing the regurgitating toilets set up by Willy Widdershins, but the plumbers were flummoxed.