water on driver's side floorboard on 2002 Nissan Pathfinder

Recently, I've had water pooling underneath the carpet close to the gas peddle. I think it's fresh water (not from engine or cooling/heating system) as it it odorless and colorless. I suspect it's due to clogged drain lines from the engine compartment or from the sunroof. Where are these drain lines and how do I unclog them? It's driving me nuts and I live in the southeast and we've had a ton of rain/snow this winter. Please advise. Thanks.

Asked by for the 2002 Nissan Pathfinder
You will need to determine if the clear water coming into your 2002 Nissian Pathfinder is due to a clogged A/C system evaporator drain, sunroof drain, or the water may actually be leak past a worn weather strip or a damaged body seam. Here are some checks you can make. In most conditions when the A/C has been running for a while you should notice water dripping from the evaporator drain which should be on the engine side of the firewall. Humid conditions will accelerate the condensation - If you see condensation on the a/c lines under the hood there should be condensation on the evaporator core if the drain is plugged the condensation can leak into the passenger compartment. You can check the sunroof drains as follows - With the sunroof open slowly poor water onto one corner of the sunroof frame at a time, the water should quickly flow out the drain. If it does not chances are the drain for that corner is plugged. If both of these checks come out OK then things get a bit more difficult. You may need to have someone spray water on the exterior while you are looking for water coming into the vehicle. Trim panels may need to be removed and carpet pulled back to help try and see where the water is coming in.
1 more answer
Sounds like a heater core to me. If the passenger carpet is wet for no apparent reason and it gets foggy inside the is usually the culprit.