wet floorboards only in one spot

I put towels down to get most of water out till my boyfriend got home with the shop vac, vacuumed it all up yesterday. Checked it this am and it was drenched again, so confused.......

Next time don't buy her a Big Gulp before taking her on a 5-hour road trip. j/k, the water could be coming from under the dash and running under the carpet to pool in the back seat area. Like Tom mentions, heater core or condenser coil...

I haven't been running the a/c lately, before yesterday it had rained 2-3 evenings prior but I had been in my car between those days also and never seen anything. I don't believe it's the heater core bc it's not wet from the passenger floorboard back, just below passenger seat back....when I've touched the carpet today it really smells like (no joke here) poop, which I know it's not just smells very bad. It's was really dark brown if that helps any. Kenf not sure if your a parent but it's so hard to resist a sweet face begging for that big gulp lol not, they(I have 2 kids) are rarely allowed to have drink in the car period.

Couple links you may find helpful: http://repairpal.com/rainwater-may-accumulate-in-plenum-tray-due-to-clogged-drains-042 , https://www.youtube.com/watch?v=_aDxd5z22B0 , http://www.passatworld.com/forums/b5-information-base/230249-water-ingress-solutions.html ; the last link refers to drain channels that may be clogged with debris and preventing rain water from draining to the ground. You may not see this type of leak right away either, but one or two days later, soaked floors... PS: the smell from the floor may not necessarily be from the liquid but from the carpet and everything everyone who sits back there has been stepping in. Cheers!

Thanks guys! Believe we finally got it all dried up, gonna check my drain holes today, ran out of time yesterday, now I just gotta focus on getting the funky smell out, nasty wet shoe smell isn't appealing at all lol!!!!!!