Whether or not the owner is liable for your fall will depend on a number of factors. First, how do you know that the water heater was last inspected in 1998? Even if you can't prove that it has been that long, an investigation into the heater, it's repair/leak history and how long that heater had been in place versus it's life expectancy can be conducted. As with any negligence case, an injured person must prove three things. Fault - that someone was negligent; damages - how badly are you...