(Video) Replacing Hot Water TankJune 3rd 2015
Unfortunately, there is no way to tell how long a hot water tank will keep working unless there are some obvious signs like rust marks on the tank or water on the floor under the tank.
When purchasing a new hot water tank, look for models that carry and eight to ten year warranty. Sometimes, you are able to purchase an extended warranty for that extra piece of mind.
When you have your new tank installed, my advice is to have a diaper pan placed under the tank with a drain to the sewer pipe to prevent any flooding in the event your tank develops a leak.
NOTE: You may want to consider a tankless hot water tank, i.e. Bosch, which has no holding tank. It heats water on demand and saves many dollars on fuel costs.
Here is a video of Shell showing you the proper hot water tank maintenance...