Whats the difference between the plastics
It suggests PVC will last about 3 years in the sun
A separate page shows push fittings not heat fusion joints, they are used on large pipes. Probaly 3inch and greater.
push lock couplings
As for water safety, the best seems to be copper from all accounts.
But nobody can afford it.
The facts are from the guberment and industry that the plastics offered today are safe for human beings.
I have read many papers to come to that conclusion.
Sure there are papers which disagree, but I look at the science, others may not. BUT, read widely and make up your own mind if you are confused.
I have been using HDPE for 42 years, so far I have not encountered any medical issues.