it's likely A/C condensate, if you park with the A/C turned on - and the front of the truck point up a hill (think driveway, etc) then the drain for the condensate will allow the run-off to go the wrong way and find it's way to the footwell.

(sorry - it seems I don't read too well before posting...)

 

9/10 times this problem is caused by the faulty design of the AC drain tube that extends into the engine bay. The drain tube sticks straight out and the incoming air into the engine bay while driving is forcing the condensation back into the cab.

You can purchase a repair kit at any Dodge dealer for about $12-$15 or you can stop by your local parts store and purchase a 5/8" plastic heater hose elbow for $2. You'll need to file or grind down the barb on one end, apply a small amount of RTV around the end and insert it inside the drain tube about 1/2". Allow the RTV to set before driving. The elbow blocks the incoming air from the AC drain tube but still allows it to drain. A real cheap, easy fix.

 

I recall reading this is caused by a leak in the gasket on the rear window,How it gets to the pass. floor is beyond me ??

 

Did anyone ever figure out the passenger side floor leak? My truck does this also but only after a hard rain. Definately plain water and not coolant. It's winter and haven't run the AC either.

 

If you use your defroster then the AC is kicking in and out dehumidifying the inside air. Not saying you don't have a leak but it could also be the AC drain tube problem also.

 

Yea I was thinking that at 1st. but I realized it only happened during hard rains. I don't drive my truck much and it sits for extended periods of time. I'll go out and check after a hard rain and the truck has been parked for days. I'll find water on the passenger floor. It runs down my mat from the firewall area. I've read all the posts on here about this problem but haven't seen a definate answer as to where the water is coming from.

 

I too am having a problem with AC drain water on passenger side carpet. I am going to try the 'add a 90 hose' idea above as I have 'snaked it out' and blown compressed air up the tube as well. It makes a lot of sense that the water is being blown back in. SW Florida and we use a lot of AC here!