A lot of water in the Saturn floorboard

It’s rained a lot in the past week or so. Several days ago, we noticed a lot of water in the passenger side floorboard - front and back. We assumed we left a window open, dried it out and forgot about it until this morning. It rained all night, the windows were definitely closed and again, a lot of water in the floorboard. We have a sunroof but the drains seem to be ok. Any ideas what might be causing all the water?

A blocked drain for the area under the grill in front could cause the front problem, but it would not cause the back problem on most cars. I would double check those sunroof drains