I'm a recently licensed plumber in MA. and the MA Plumbing Code permits PEX to be used in residential buildings, up to and including 3 stories high. If the building is higher than 3 stories, PEX is not permitted at all. PEX in commercial buildings is extremely limited - Reverse Osmosis filtering.

I'm curious about other States and other Codes.

Is PEX permitted in buildings taller than 3 stories in your States?

Thanks for any responses.