Add Pex to the mile long list of things that could give you cancer:
https://calpipes.org/ProtectingCalifornians_PEX.asp
We’re not sure about pex causing cancer and all that but Pex is definitely not a material we use for interior water pipes. We prefer CPVC because it has stood the test of time. CPVC requires more plumbing skill and “neatness” in the way that pipes are run. Pex comes in a roll and it basically a big hose that doesn’t have to be run in straight lines. Also pex is connected using another crimp ring system. Crimp rings were a huge culprit (not the main culprit: https://www.callplumbingexpress.com/replacing-polybutylene-pipe) in the current rash of polybutylene failures. CPVC is chemically welded together with solvent and glue. If a CPVC joint is going to leak, it will do so in the first 12 hours under pressure. Crimp rings that are improperly installed could pop apart at any time.
The moral of this blog post is that you should always go with CPVC or copper. Pex is not a good option for interior water pipes. That is all.