There is a sunroof drain tube that runs from the corner of the sunroof to the driver's "A" pillar. That would be the one you'd want to take a look at. Usually when they are an issue is when they spit or get disconnected at the roof and leak unto the headliner, so I have my doubts as to it being the cause for water on your driver's floor. You may need to have someone looking under the dash with a light while someone sprays water with a hose on the outside. In my younger days, I would recline the driver's seat as far back as possible and sorta sit upside-down, with my head under the dash. It was really awkward and uncomfortable, but I did what I had to do to figure out what was going on! Of course, we didn't have smart phones with video capabilities like we do today, so maybe that's a way of doing it? All I know is I'm too fat and old to be stuffing myself under any more dashboards!