Where is the water coming from?

Started the car yesterday ('88 3.5 efi) to turn it round on the drive, once i'd stopped then engine after a few minutes i noticed some dripping from the exhaust at the connection with the centre box, obviously a blowing joint! the dripping was water, at first i thought condensation, but now i'm curious, any thoughts as to where it could be coming from?

just condensation, nothing to worry about

Might explain why the exhausts rust so efficiently!! I figured as much just wanted to confirm it. I had a look at the oil filler cap and no mayonaise so was pretty happy after that!