Hello.

About 2 Wks. Ago I discovered that my water faucets were not working properley.

You turn one on and its fine, but turn on another and the water output is as if you had shut

Off the water supply. Help?

Do you have a whole house water filter there?

Are you on city water or well?

Are the water lines copper, steel, or PVC

Yes I have a Whole house water filter which I have regenerized, My water supply comes from the city and my water lines are copper.

Regenerize? Sounds like a water softner not a filter. Tell us more. If it is a water softner try flipping the buypass valve over to take the softner out of the mix.