German law reserves 53 trades to those holding a Meisterbrief. The Handwerksordnung recognizes roughly 130 trades, divided into Anlage A — the 53 where a Meisterbrief is legally required to operate independently — and Anlage B, around 41 further trades where registration is required but no Meister qualification.
The law states the rationale explicitly. These are trades where improper execution poses a risk to public safety, health or life. A poorly installed gas line, a defective circuit, a compromised roof.
The qualification involves 1,000 to 1,500 hours of coursework across four parts: technical, theory, business law, and the competence to train apprentices.
A German plumber is not someone who is good at plumbing. He is someone the state has certified as having mastered it.