There are a few possibilities.
The water is probably coming from the airbox which allows fresh air into the cabin and drains out water via a"Gutter" type system which drains into the front fenders behind the front wheels.
The opening atthe back of the hood near the windshield wipers is the inlet and a few things can casue leaks and overflows.
Overflows are caused by years of leaves, debris, etc. Clogging up the drainage system and allowing water to build up to where it runns over the gutters into the air box tight into the blower/ A/C box.
This is something to definatelty get taken care of as the blower motor can short out, the A/C evaporator will eventually grow type of moss that will clog the A?C and cause it to fail.
Some cars also have the computer situated under the passengers' feet and that can get soaked and they are very costly.
The other thing that can happen is leakage.
Sometimes the windshield will leak due to deteriration and or damage from accidents. Also, the windshield wiper cowl is held in place by plastic body pins which can leak as they get old and drip into the same area.
Either way it sounds like you need to remove the blower motor and the airbox above it. That should be the recirculated/fresh air box. Once you remove these, you should be able to see whether the box is pouring over or if something is leaking.
To fix it, the wiper cowl needs to be removed and the air box cleaned out and new pins/plugs used to re-install the cowl.
I used some silicone to re-install my cowl just for a safety measure.
Let me knwo if you heed any more guidance.