I had never seen this before moving into our new house but the way the floor plan is, our current water heater is actually under the house. One morning when I felt like I was not getting enough hot water for my shower I asked my husband to look into it. When he finally did find the tank it was below the house. Luckily though it stays pretty moderate there and we were given the recommendation to have a heat pump water heater used in conjunction with the current set up to get more hot water into the house for future use.