: : If you are talking about the water supply, then copper is probably the preferred system in alomst all parts of the country. There are a few areas where water chemistry is a problem for copper, and some well systems this could also be true.

: CPVC is found in some modular homes and other areas. No plumber in his right mind would put just a glue joint between 70PSI and your living room.

: Never heard of HDPE or Polypropylene being use.

: Polybutylene was used for several years, and hundreds of lawyers have retired rich off the lawsuits, which are not over yet.

: A system called PEX ( cross-liked polyethylene) is gaining in popularity rapidly. Old farts like me will be slow to accept it even if it is great.
: It does require special tools and special training; it will not be a do-it-yourselg project.

:
: For DWV I like ABS even though Sylvan will cut me out of the will for even mentioning it. He likes nothing but cast iron and you can't hate him for that.