I am replacing galvanized piping with PEX piping. I will only be replacing the piping in the basement and leaving the galvanized piping risers to the floors above. I will be using brass PEX fittings. Do I need a special fitting such as a dielectric union/coupling to connect from the brass PEX fitting to the old galvanized piping?

Hi sodler,

You don't need any union between the galv. And brass pex fitting, we use brass couplings when transitioning from galv. To copper. So your fine. Happy plumbing.