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 its important that you get a pan that has an outlet tap. A washing machine that has a ruptured supply hose or tank will allow all the water coming to the appliance to pour onto the floor until the supply is turned off.

Remember to put a plate on the outlet to the floor drain or sump pump if you have one handy. If you have an upstairs laundry, install a sanitary tee in the drain pipe for the washing machine. It is usually located above the plumbing trap, but below the bottom of the drain pan, and pipe the outlet to that. If possible, pipe the trap down to a lower floor, and then tie it into a drainpipe making sure, of course, that there is a trap between the point at which it ties and in and the main drain leaving the house.