CPVC vs PEX in new home
Why is PEX not able to be installed in a three story house 


The Building Codes require different electrical and plumbing beginning with 3 stories above grade. Many multifamily dwellings in the past decades skirted this code by building the first story half in the ground and two stories after that. There are not very many three story residences but apparently the one you are buying is one of them.


  and is there more risk of CPVC developing problems than PEX or copper?


No, CPVC has been used for decades and is a reliable and cheaper alternative to copper and as reliable and cost effective as PEX.

Rest easy and enjoy your new home!