I am assuming its called the passenger floor panel, On a rainy day it gets ridiculously wet. I heard I normally happens to ppl who doesnt have splash guards and mud flaps. I have all of those and it still gets wet. I even put the car on a lift to look for rust spot underneath and couldnt find anything.

Any suggestions as the why it gets wet??? Driver side stays dry.

 

Sunroof? May be leaking from there. Maybe even the windshield.

 

I wish I had a sunroof. I settled for a DX in haste to get a ride I doubt its the windshield but if it was wouldn't I see water else where such as the dash,glove box, etc. Would a leak from the windshield even cause the floor to be really dampened as if my lame cup holder spilled an oversized bk drink???

 

Could be the lines running into the heater.

 

was your windshield replaced? some cheap replacement windshield companies use junk sealer and itll leak. a/c under dash could be leakingtoo.

ive been running without mud flaps for over a year now, no water build up. if your leaking though, id saran wrap or put a ziploc over your ecu. the plugs are on the bottom side of it, right at floor level. you dont want water in there!

 

Does it leak all the time or only if you have the A/C on? If only when A/C is switched on, check your drain line for your Evaporator, it could be disconnected and instead of dumping water through the line and onto the ground underneath the car, it runs out into the passenger side floorboard.

If A/C has nothing to do with it check what these other guys said.