On Wednesday, August 16, 2017 at 4:50:57 PM UTC-4, wrote:
I want a supply line to source from one of two water mains. I was looking at 'y' valves but the ones found all suggest they are 'marine' type (which does or doesn't make a difference). Is there a common Y valve used in home plumbing?

or two regular valves...
if this is potable water,
you should also probably require one or two backflow prevention valves so one source cannot back-feed to the other.

mark