What is the difference between chlorinated and rigid PVC, especially with respect to pipes?
If you’re looking for a structural pipe for rainwater, look into Smooth Lined Corrugated Plastic Pipe (SLCPP). It comes in sizes from 4″ diameter to over 72″. If you’re looking for something around the house to collect rainwater from the downspouts, plain old 4″ schedule 40 pvc, or SDR 35 should be adequate.