Water under my floor mat on the passenger floorboard on the passenger side of my 2004 toyota

Feel the water and smell it. If it smells sweet and fells oily, is is coolant. If is isn't oily and has no real smell, it is water. There is a tray under the evaporator and heater cores that catches water/coolant and drains it via a tube thru the firewall to the outside of the car. This tube is probably clogged and needs purged. If you have coolant on the floor, you'll need to replace the heater core. If it is water, purging the hose will solve the problem as the water is just condensation from the AC coils

Often the floor of the passenger side become wet if the drain pipe of the evaporator is:
- Bent or twisted.
- Clogged or,
- There is any obstruction in its routing.
The drain pipe is a rubber hose about 14 mm in diameter, located just under the evaporator (cooling coil) casing on the passenger side.
The most easiest way to clean the pipe is to take it out, wash it from inside with water or to blow a compressed air slowly through its distal end while leaving it in place under the body.
Note: Keep your eyes away while blowing the air.
Hope that it works.

is it water or anti-freeze
if it is anti-freeze i would have to say your heart core is leaking bad
also check you engine coolant and see if you have lost any
get back to me and leave some feed back
hope i was a help

I would say you have either a bad seal on the windshield or the seal on the passenger door opening.

air conditioner/heater compressor's or evap canister is leaking on the floor. It is very common with the focus. After time that water begins to stink! Try silicone to seal the leaky component which would be above the floor mat.

You could have a leaking windshield seal, and its running down the inside of the dash and onto the mat. Has the windshield been replaced?

i would check water in radiator as sounds like the heater box under the dash is leaking and will certainly end up on floor

The 05/04 Pacifica did not come with an elbow tube on the drain line for the AC drip pan. As you drive, the air flow into the tube pushes the condensate water back into the pan which is inside above the passenger floor board, the drain line is under the hood on the firewall. I spoke with the parts guy at the local Chrysler dealer, he sold me a drain tube for the 06 (~$10) and I installed it, wasn't too hard to do from the top if the engine is cold. The elbow slips on over the drain tube. Make sure to point the tube down. It only took one trip to start seeing water drip out of the tube and the floorboard started to dry up and almost three years later, the floorboard is still dry.

i know this is old....but find newer thread for a clogged ac valve elbow. It solved everyones problem and is not the core like other cars.

yes, your a/c drain is most likely clogged up causing the water to come inside the cab. see your nissan dealr. warantee issue. 3 years 36000 miles.