I have water leaking under the front carpeting on the passenger side near the door when it rains.

When I lifted off the sill cover and peeled back the carpet it appears to be coming from underneath a rubber lining the runs under the lower dash behind the glove box and heater/AC box and fan assembly.

When I removed the fan and felt inside I could not find any evidence of water. Also:

• Removed the plastic air vent under the wipers and poured water down the windshield and into drain area and could not replicate it.
• Lifted the plastic insert forward of the roof rail, flooded it with no luck.
• Peeled back the fender liner to see where the water runs down from the drain area under the windshield and cannot see where it could be entering.
• Not coming from the door seam as I watch from inside with it closed and water spraying on the side of the vehicle.
• There is a fresh air vent behind the drain area with raised metal edges but water never makes it that far back when I flood it.

Any ideas as to where this water is entering?

 

I have the same year Odyssey as you and have the same problem with water under the carpet on the passenger side. I also lifted up the rubber mat and it looked like the water was coming from under the mat. Likely running under the mat from somewhere above. I hadn't driven the van in awhile but there had been a couple of heavy thunderstorms come through that saturated the carpet. Did you ever find out what was the cause/where it was coming from?

 

Finally solved it about a year ago after peeling back the headliner and removing the passenger side A-pillar trim piece on the side. It was leaking from the windshield top right corner and running down the A pillar, then under the rubber matting that's behind the dashboard and floor and then seeping through the carpeting. Had the windshield replaced as the previous replacement had a lifetime warranty. When the windshield was removed there was section of sheet metal where the windshield was glued on that started to rust and separate from the seal. Dry as a bone since the replacement.