Water leaking onto the rug on passenger side back. Had it Last October

yes, back seat floorboard.

No water in front floor? Unusual to have water in rear & not front.There are ducts running under front seats but should find front floor wet as well.With car running and a/c on for say 5min. look to see if clear water drips out under car on pass. side if it does then your problem is an external leak.Rain,wash water ect. Poss. door or window seal. Does the car have a sun roof?

Most of the water was on the rug on passenger side in back (flooded amounts). Most seem to come in around where the controls for moving the seat back and forth. A very little on rug in front,really none to speak of. No seepage outside the car, no rain. Did end up going to the dealer and was told "spiders probably died" in the ac tubing causing it to block it. He came in and showed me the filter which had some dirt in the cracks, replaced this and blew out the tubing at the tune of $100. Rugs still soaked since the extractor was unavailable. Still not convinced!! I think if this is a common problem with Toyota, they should pay for this.

You will have to vacuum with wet/ dry vac. It will take a very long time to dry on it's own. I would still run the car with ac on and see for yourself that water is dripping out on the ground!! Good luck.