I drove in some pretty hard florida summer rain a couple wks ago, next day the windows on the inside were all fogged up and I found the drivers side front carpet was soaked. thinking I drove through a puddle and water got in a spent few days drying it out. week later it rained hard again but the car just sat in the driveway, well the next day I got in it and same problem!!!
took it to mitsu dealership and suprise, they could find leak! he said a/c was not clogged. I noticed on here that heater core can leak? but im guessing they checked that and as it happened twice in the rain it wouldnt be that.
Im so mad, and now I will have to sell it if I cant figure out whats going on as the carpet will be ruined.
Anyone had this happen to them? I also think if its a leak it a slow one so the carpet doesnt get wet right way, hence showing them no signs when they water test it

First verify if it's water or coolant. If it's coolant than it's the heater core. If it's water, then you a/c drain is probably clogged.