We're getting water in both footwells in ours. I think I've concluded it's the door weatherstripping. It's lost its grip on the pinch weld, and droops also.
I'm going to get some new weatherstrip, and add some silicone adhesive to the pinch weld when I install it.

 

Do you have a sunroof? The drains could be plugged if you do.

 

No sunroof, and nothing up the inside of the firewall is wet. Seems to be running down the inside pinchweld, so water is getting behind the weatherstripping.

 

Use baby power on the door seals and then run water around the doors. That will show where the leaks maybe coming from.

 

I've had good luck using fog machines (like for Halloween special effects) to track down seal leaks too. Just plonk it in the car for a while and see where it comes out.

 

That's actually a good idea. Just need a source of dry ice.

 

That would work too, but I was thinking the ones that heat up that fluid stuff. Don't know what's in that fluid, but it doesn't seem to leave a residue or smell. The same can't be said of mineral oil based ones for evap testing.