you should be able to tell if its water or antifreeze in order to determine its origin...there is a thread on this site about the common problem involving the leaking AC drain and how to re-route it, so do a search for that thread...pull up the carpet on the passenger side and see if you can locate the leak...I think there should be a drain hole in the floorboard, it might be clogged...if there isn't one, it would do no harm to drill one where the water is accumulating

 

Also could be the sunroof drain hose that came off that is a very common problem also.

 

How about mop the water up and wait until it comes back to see where it is coming from ? People that by old cars should be prepared to deal with issues like this. Otherwise buy a new one. What did we do before we had the internet. We used the brain God gave us. ...J.D.

 

Drop the head liner, get some small hose clamp (preferable the screw type), there are 4 small rubber hoses on each corner of the underside of the sunroof. Work them loose, slide clamp over hose and reinstall. Becareful not to tighten too much as the bibs off the sunroof drain are plastic. Replace headliner. Take some trimmer line and a water bottle and pour some into the sunroof drain (sunroof needs to be open of course). Gently push the trimmer line down the tiny holds in the corner of the sunroof drains (they are kind of hard to see, get a flashlight). Look for water to pour out onto ground underneath car as it should. Problem fixed. Both of my 3Gs had clogged sunroof drains and my 01 GT had the notorious AC condensate drain problem. Also, open the rear hatch and check the two drains in the jamb (one on each side). They get clogged too.