Galveston Texas,
I am renewing galv. Plumbing for CPVC and I want to lay it on top of the attic joints or does the code say I have to run them trough the floor of the attic. Most of old piping is also on top.

You can keep your new pipe on top like the old but I don't really do much CPVC any more. Have you considered PEX. Cheaper than many other options and you can snake it in to some tight places.

Also for hot water?

Pex is for both hot and cold. You may run your water pipes anywhere as long as they are secured with pipe straps. Good luck in whichever way you go. Tom

Thank you!