Hot water heaters do not usually catastrophically fail. It is usually more of a leak thing. You can put it in a pan to catch a slow leak. You can also put a water leak sensor under it (an alarm goes off if water is detected).

How long have you been in the house? Are you sure it is dry through all seasons? Through 100 year storms (our region just had a "super storm", they are referring to it as a 500 year storm). Serious water damage in the basement is not usually caused by plumbing, it is caused by storms.

In my area basement drains are unusual. Most people have a sump (with pump) if necessary. The best thing is if you have perimeter drains (inside and outside the footing) that drain to daylight, but that has to be done during construction.

Thanks Sue
We bought the house 4 years ago and have rented it out. There has never been a problem with any water and we just had the worst stormy weather here in bc the last couple of years.