Go back and check that water problem. If the tank were to over heat it would re leave itself through the safety valve which is outside and that water should not be able to get back inside to the floor.
Some unit had a winterizing bypass valve on the side of the heater. That valve has been known to loosen it's flare fitting and leak.
If you do not have that valve take a good look around the other fittings on the heater. Poke the floor around the heater with an ice pick. If it is soft the leak has been there for some time.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles