Is dielectric union necessary?

I am transitioning from galvanized to pex. The pex fitting is brass. Do I need a dielectric union, or can I just use a simple 3/4 brass pex connector?

I have looked at numerous forums and can find no consensus on whether a dielectric fitting is necessary when transitioning to brass.

Thanks much for help.

To transition from galvanized to PEX, you can use either a brass or a plastic fitting.

A dielectric is used between copper and galvanized. And not always there either. If I'm plumbing in Bellevue WA, I use a 6" brass nipple between copper and galvanized.

Brass and steel are compatible, Otherwise we could NOT use brass valves with steel piping.