flooded floorboard

I have a 2003 Impala LS. My car sat through the rain and wind of Hurricane Katrina (my area did not flood). The morning after the hurricane, I got in my car, and discovered that the passenger floorboard had standing water in it. The area around the window, door, and windshield was dry. Nothing was wet except for the floorboard.

This past weekend, we got very little rain (about .5 inch) from Hurricane Rita. Again, the floorboard was flooded. Again, nothing else was wet.

I've taken my car through a car wash between the two hurricanes and no flooding occurred.

My car was parked both times, with the engine dead, and the floorboard was flooded when I got in, before cranking the engine.

One more thing to add, it is the very bottom of the floorboard that is wet. None of the carpet on the slope up to the firewall is wet.

Any idea what's causing this?

it's the weather stripping around the bottom of the windshield, by the plastic cowl strip. often the moving water of the wash won't penetrate the inside of the dash, down the firewall, and to the floorboards...but rain often will...Let me know what u find, but I'd bank on the weather stripping previously noted.

I have a 03 Impala 9C1. I have found after a rain the passinger side floor closer to the door has alittle water , not much. A few drops on the rubber floor mat. I believe it is coming thur the door weather seal, somehow. Not sure yet. Car washes are fine. Vehicle sits for a while , it rains. Few water drops on the floor. Nothing else is wet. Thought i saw a very small H2O trail from the door seal. Dont know for sure. Hope this helps. STAY SAFE
MIKE

Are you parked on level ground when this happens ? If you are parked downhill, look to the back of the car. Like the rear window. I had an 89 celeb that leaked through the rear window till I removed the window and resealed with urethane or eurethane, just do not use silicon sealant ( actually in my opinion and this is just me talking, you may have different results, should not be used on anything in your car especially the engine for gasket sealant). Also had a small leak around one of the hinge supports for the trunk that I did not find till I got in the trunk with a flashlight and some one running water over the trunk. Which I think is not going to happen on the Impala, different design.

I had a similar problem that left me with 3 inches of water on the passenger side floor,the exact phrase was hvac intake seal,located near cabin filter plastic cover (the cover on the outside near wipers) apparently in my case the wiper tore the seal off after winter freeze, if it is this water will leak from the light bulb under the glove box it will look as if the bulb is leaking, the water comes through the fan assembly

I have been having the same problem with my 03 impala. I had to have the windshield replaced and it seemed to start after that. So I called the guy back who installed the windshield and he told me it was some drain under the hood that couldn't drain water fast enough so it would run inside. He said that all GM cars do it and there really wasn't anything I could do about it. I am really finding that hard to believe when I didn't have any problem with it leaking until the window was replaced. And when I say leaking I mean standing water!!! My concern is the smell it is going to leave in my car. Anyone know if this could be true about the drain? Thanks!

I have been having the same problem with my 03 impala. I had to have the windshield replaced and it seemed to start after that. So I called the guy back who installed the windshield and he told me it was some drain under the hood that couldn't drain water fast enough so it would run inside. He said that all GM cars do it and there really wasn't anything I could do about it. I am really finding that hard to believe when I didn't have any problem with it leaking until the window was replaced. And when I say leaking I mean standing water!!! My concern is the smell it is going to leave in my car. Anyone know if this could be true about the drain? Thanks!
I had the same problem with my 2001,took it to the dealer and they said (from the invoice) "found weatherstrip under cowl on right side coming off reinstalled weatherstrip" this was with 9700 miles so it was covered under warranty

yeah sounds like the weather striping on top of the passenger compartment air filter