No pressure, but a lot of stress!

I recently purchased an house that was constructed in 1928. During my inspection, I noticed that the water pressure for all the hot-water outlets (kitchen, bath, and washing machine) was extremely low, so I changed out the water heater hoping that would solve the problem. Unfortunately, that did NOT solve the problem. From what I saw when I changed the heater, I suspect that the copper piping that provides hot water throughout the house is corroded. Now I'm contemplating replumbing the lines with PVC.

Since I'm a novice, I'd like to know what things I might consider before I start. Where will problems likely arise? What are my alternatives, if any? For example, I'm not sure whether I have to replumb the ENTIRE house or if I can replumb only the hot-water lines? Will I have to change out the cast-iron drains, or will I be able to connect the PVC to the iron?

I'd be grateful for any advice. I'm a novice, but I'm handy enough that I can do this with a little forethought.

THANKS!
shawnkey
Little Rock, AR

pressure

It would be an extremely unusual situation if your copper lines were the problem. You cannot use PVC and if you use CPVC, you will notice that the opening is about 1/2 the size of the copper tubing it replaces so you will either have a bit of a pressure/volume problem afterwards or you will have to upsize the piping. Maybe you need a plumber to come in and find out what the real problem is before you start spending money repiping it and then have the same problem afterwards, like happened when you impulsively changed the water heater.