At the top folder (not within a subfolder), there's a button on the left to start a new thread.
PVC is not for potable water, well at least on the hot side. CPVC is allowed for potable water, both hot and cold.
Are the joints that are failing threaded or glued? If threaded and you tighten them too much, the stress can cause them to split eventually. Pipe threads are tapered, and the tighter you make them, it acts like a wedge that could split just like when you split a log.
Post a picture if you can (scroll down when posting to 'manage attachments for the specs on the sizes and file types available - you'll probably have to reduce the resolution of the file to upload it).