When it comes time to clean your hot water heater, it's important to install a drain pan which is sometimes referred to as a drip pan. It doesn't matter if you are working on a water heater or even your clothes washer, putting a pan under it to catch any leaks is a great way to track the water flow away should it become a flood. If you have a dishwasher, a drain pan is not usually installed under it because this type of appliance is typically connected directly to a supply pipe. It doesn't heat the water, thus minimizing the chance of a leak.

A drain pan is a necessity, especially if you're putting in a new hot water heater or washing machine on the second floor or higher, or above your finished basement. This is especially true if it is going into a concrete- floored utility room which is just off a room with wood or carpeted floor. Remember, with any pan that you get, a hot water heater will hold a lot more water so it