Water in footwell
got a nice puddle in the passengers footwell where is it going to be coming from?
heater matrix is a gd start check ur coolent levels, if they have droped then take dash apart till u find it, and run up to temp to find the leak.
If i was you then i would stick my finger in the fluid in your foot well, yes thats right stick your finger in it then lick it. As strange as that seems, its what most mechs do, if it is sweet then its anti-freeze then like jon said strip dash until heater matrix is apparent. If not sweet then rain water has found its way in.
I will go do some tasting later on and see if it's anti-freeze or not. if it's not I guess i will get the hose out and see where it's coming from.