2001 interior water leak

My daughter has a 2001 Impala she just purchased. After the last heavy rain she found the passenger side had about 1 - 2 inches of water on the floorboard. Have done some "google" searching, have found that this is a problem with that car, but so far have not been able to find why it leaks or how to correct.

Any help is appreciated.

Had the same problem with my wife's Impala and thought it was a rain issue. More than likely it is the drain tube for the A/C unit, which includes the defroster. If you look under the hood of the car down low on the passenger side firewall you will see a little black hose that sticks out a little and tappers down. This is used to drain the condensation and such. I know it sounds like it can't be this but 9 times out of 10 this is the culprit. My wifes car had about 2 inches of water on the passenger side. Anyway that hose is very small at the end of it and it gets clogged from dirt and debris. We cut the hose off about a 1/4 inch up farther to make the hole bigger. This completely solved the problem. Remember it is very low on the passenger side fire wall under the hood. It is easy to miss and it is made of Rubber.

If it is clogged it backs the water runoff into the passenger side floorboard.

Cutting off the end of the hose may help but the hose can be plugged all the way back. Find a full service station and ask then to blow out the air conditioner drain line.

They'll use compressed air, and if thats the problem it will be solved.

On a side note, every Impala I ever owned, or saw, had a windshield that leaked (eventually). but I havent owned one since 1986 model.