Further to Bob's post, below, when I took delivery on my car from the US, I also had a great deal of water on the floor. Following the advice from the group, I checked all the hoses that join the various steel drainage pipes: from the air scoop down through the firewall and thru the top of the footwell area above the cosmetic card pieces on driver and passenger side then back into the lower part of the firewall and out into the engine bay via the 2 rubber ball drains (if still present); also the hoses that link the drainage pipes in the soft top box to the drainage pipes inside the rear panels that direct water out of the car through the sills. Three of the four hoses were either shot completely or leaked. I have not subjected the car to much water since then, so I do not know if I have rectified the problem, but I have certainly addressed it in part. I would check these rubber hoses.
Also, remember not to neglect the carpets under the seats - like I did. They were equally very wet. All in all it cost me 2 new floor pans on the drivers side.
JH