| Worst part may be fixing any walls you have to rip out. You need to use CPVC on hot water lines. PVC s cheaper, but won't take the heat. Just unscrew the galvanized pipe. Near one end or the other, there should be a fat nut on a fitting. It is called a union. You can unscrew the nut without turning the pipe. You may need to apply penetrating oil, a large wrench, and a hammer to make the pipe unscrew, maybe if worst comes to worst, a torch. A hack saw or Sawsall can be a big time saver. Show a little gentleness at the hot water tank and shower. You want to turn the pipe out leaving the threads undamaged. Broken off pipes can be removed with difficulty.
CPVC if the kind of tan colored stuff next to the PVC. Most water lines are what is called 3/4'' pipe. It is about 7/8'' OD You will need a male pipe adapter to screw into the tank, elbows, ball valve shut offs, and pipe. The shower may be half inch pipe thread. If you are replacing the cold water lines, you can use PVC for them. Just buy a can of multiple purpose cement and use it on both. Also a can of cleaner/primer. You may want to instal CPVC compression unions near the end so you can take things apart without a hack saw.
Lowes has a better selection of CPVC fittings than Home Depot and lower prices. Ace or Top Value hardware maybe about the same price and more likely to give you help. | 
Linear Mode
