My plumber is an American.
Service plumbing requires a lot of talent and investigative thinking to do well, like oil changes and tire shops, some of the plumbing has been peeled off by drain companies and lower-level skill sets, but when it comes to repair work sometimes real intelligence is needed.
There are customers out there who when you are the 5th or 6th plumbing company they have called to solve their mystery, they are frantic.