I'm still chasing an interior water leak. I have found the route the water is taking to get in - the seal between the clutch pedal and the firewall. I'm going to replace the seal, and also silicone the hell out of the entire area.

The water is getting in through the driver-side hood vent. It is pooling in the area where the pedals mount, and leeching in.

So three questions:

does that area have a drain hole? Maybe mine is plugged. I can't see one, but it's pretty crowded down there.

Is the plastic piece of the vent in the photo (circled) missing a piece? I can see the water pouring into the engine bay from this piece. It looks as if the water has nowhere to go but into the cabin.

Is that plastic vent actually functional, or just cosmetic? I'm going to plug it if it doesn't actually do anything.

 

Not certain, but the plastic portion above what you have circled is fairly easily removable. Remove the wipers and remove that plastic, and you should be able to easily locate your leak.

 

I just went and looked at my car, that part you have circled is normal. So it sounds like you have a clog. I would remove the wiper blades, then that plastic cowl cover and look for any clogs. Typical leaves or pine needles will collect down in there. Should drain out along the inside of the fender. Also check around that area where the pedal mount, water should be able to drain from that area as well. Again most common issue is leaves, or possibly some critter tried to make a nest down in there.