My friend has a Mitsubishi Galant, I think year 2000. When he has the AC on and he makes a left turn, he hears a water rushing sound under the dash going away to the right, and then water appears on the front passenger'* foot well.

Any thing I can check? Remember I am only a car novice I am just mechanically inclined, so I would probably need clear directions or pictures to know what I'm doing.

The vent tube on the EVAP

Yep. Or a half can of beer'* stuck behind the dash...........Sorry, in one of those moods.

haha been drinking?

I told him it shouldn't be expensive to have a mechanic clean it out, I'll post back what he finds.