Rep Power: 0

This has been an ongoing problem with my car. Our Summer in WA just finished (yep, its September and it's already getting colder and raining at ton), so this has started again.
I've noticed that right underneath of my front passenger and rear passenger's carpet gets really wet once it's been raining for a few days.
Window seals look fine, except for that black plastic trim part that runs vertically in between the windows. It's popped off on the top.

I have done some research but it seems like this issue for most people is happening in their trunk and/or on the driver side. My driver's side has always been dry.
I will try to get that trim popped back in with some sealant around it, but in the mean time does anybody have a suggestion?

Thank you!

 
Rep Power: 244

Leaks can be hard to pinpoint as they can come from a place you wouldn’t suspect. I would remove the carpet so it can dry out and with the carpet out you might be able to see a water trail. You can start just randomly sealing things but that could take a while. I would start by fixing that piece that has popped off.

 
Rep Power: 0

I had a similar problem with my '94 civic cx. Found it was leaking into the heater intake under the cowling on the passenger side and constructed various dams which seem to be working. I glued my trim back in place with windshield sealant. Good Luck