Most car companies will give you bumper to bumper coverage.
If it was bumper to bumper, it would (although it never truly does) cover everything, and in my mind, salt water is under the designation of everything.
The information provided on the side panel under the user's name states that the vehicle will "when underwater, the driver and passenger are enclosed in the vehicle thanks to light weight body components made of futuristic Carbon Nano Tubes and are supplied with fresh breathing air by the self-contained on-board system." So, you won't have to wear a scuba suit or anything like that.
I thought that was a little strange too. That would be inconvenient to have to wear a SCUBA mask and (optional) wet suit or swimming suit when you drove it.
But what type of people would need to drive in the water anyway. It is cool, though.