Personally I would ask the Builder how much money he honestly expects to use TOXIC plastic.
Why not ask this builder if he would allow his children to drink water from this type of piping?
Ask the builder to show you ONE piping system made of plastic that lasts the time copper is still going 3000 YEARS.
If soil and water conditions allow TYPE L tubing above ground and TYPE K below ground.
How does this builder dispose of LEGALLY plastic?
Decisions decisions have a great one