2005 Chevrolet Silverado 2500HD Water on floorboard

Hello, and thank you for this site.

I keep getting water on the passenger and drivers side floorboard after it rains. I have run the garden hose over the cowl and am able to see the water leaking down the passenger floor from behind the blower motor. Any suggestions on this? Windshield leak? I have seen maybe blocked drainage with leaves? Possible blocked A/C drainage? Any help would be greatly appreciated. My days of troubleshooting seem to be numbered with having the little ones.
Peeking in that grill under the windshield would show water in the bottom of the pan with a flashlight, read recently that Jim Fairbanks has a flashlight. AC drain can also be plugged, even if you don't use the AC, that water has to go someplace.

Recall the last time that happened to me was with a 78 Fleetwood, my eight year kid got all teed off because he tossed his Ninetodo magazine on the floor and it got soaking wet when it started raining. Think on a Caddy they would install that chicken wire under the grill, and you quickly learn, you don't have a blower motor but a leaf chopper instead. And yes we have leaves in Wisconsin. So took all that apart and cleaned it, and did install chicken wire under the grill for a permanent fix.

Got the weird thought our vehicles were made for just the showroom, that idea really held weight when they started wrapping the doors half in the roof. Can't open your doors if caught in an icy rain. But you don't have that problem if left in a heated garage.