Water Leak

[Roadrunner]

What is the most likely source of a water leak that shows up in the battery tray trying to make battery float?
Car is parked on flat ground not being driven. Mainly notice after torrential rains.
Other areas are dry when I get around to checking on it.
There is a little surface rust near bolt on passenger side that holds the seat back in place.

[96 SSEi]

that's weird, and dangerous!! recreate the rain with a hose and you will find the source

[nos4blood70]

I would start with the passenger rear door water shield, and sunroof drains if equipped.

[ddalder]

I'd actually look at a source in the trunk. The area where the battery sits is elevated above the floor pan and it's more difficult for the water to move "uphill". The door water deflector is certainly a possibility. I had some problems with water entering at the top of the rear shock tower on my right side. Water would spray up while driving, run down the tower inside the trunk and down behind the seat collecting around the battery. There are also left and right rear sunroof drains located in the trunk. These are high on the suspect list. Do you have water in your spare tire well? I can't even begin to tell you how many different sources of water leaks I had to deal with.

The bolts that secure the seat back and seat belt buckles in place do pass through to the outside of the vehicle.