I've been trying to solve this water leaking problem into the driver side floor board for at least 9 months now. Background: I have a 2000 LS1 which was my primary car for the last 15yrs. Bought a new car last August and Saturn was just a vehicle in the yard. It never leaked water before until after it was parked. This only happens when it rains. Prior to two weeks ago, the car was only used maybe once every two months for landfill runs. That rulled out any AC or heating leakage and the car really wasn't used. I had a GM service department look into it and of course that was a waste of money. I had the windshield replaced a few months back because it needed it (hard to see out) and there wasn't any signs water had ever leaked past the windshield. I checked the seal around the driver door and it seemed good. The glass guy suggested water may be leaking through the fresh air cabin intake and that the drain ports may be clogged and water built up until it drained into the car. I pulled the cowl off and there was a good amount of debri there that may have kept water from draining. Made sure that the drain ports I found were not clogged by forcing water through them. However, after all of that, it rained that afternoon and floor was wet again. The fresh air intake seemed the best answer to the problem but not sure. Could there be a seal I need to check or drain port I'm missing or do I need to look at something else? The only drain ports I found were on the left and right sides and the water drained just behind the front tires through the fender it seemed. Could the water be draining in the wrong place and some of it goes in the car. Thanks for any suggestions.

 

My first idea was the cowl drains, but it seems like you've addressed that already. Does the car have a sunroof, by any chance? If so, then you need to check the drain tubes on it. If not, I don't have a clue as to what to tell you. Sorry bout that.

 

When the seller brought me our LS2 it was drenched with water on the drivers side as well.

After doing all this tearing down to track it's source of entry I was able to get it solved.

It was entering the drivers side door panel. Someone had replaced the factory door speakers with aftermarket ones and didn't seal off around them.

There is a drain hole at the bottom of the speaker opening so it drains back into the door instead of the interior.

 

No sunroof.

However, I will check the speaker as I did replace them. I guess a seal may have finally broken down as I replaced them about 8ish years ago. Thanks for the suggestions.

 

Good catch, tooter. I hope that works for him.