Mario is copyright Nintendo.
Nintendo’s Mario is perhaps the most iconic, most well-known plumber of all-time, even though its dubious that he ever does any actual plumbing.
Introduced by Nintendo as “Jumpman” in 1981 as the protagonist for the arcade game Donkey Kong, Mario’s original profession was actually carpentry. He was renamed to Mario for Donkey Kong Jr., but wasn’t a plumber until the game Mario Bros. in 1983 (at which time his slightly less-famous green-clad brother Luigi was introduced).
Since the release of Super Mario Bros. for the Nintendo Entertainment System in 1985, Mario has become the one of the most well-recognized fictional character in the world and the Super Mario series has become the bestselling video game franchise of all time.
While Mario’s expertise in plumbing technique is somewhat questionable, plumbers couldn’t ask for much better popular representation.