I've just redone one bathroom and found that the nipple between the brass fitting back in the wall and the stop valve for the toilet tank was gray PVC, such as one uses for sprinkler systems. I assumed that this was not kosher and replaced it with a galvanized one.
Now I have come to the second bathroom and found that the galvanized nipple is seriously corroded. Perhaps the PVC nipple in the first bathroom was there for a reason?
What is the correct material to use here?
Perce