What Is a Water Heater Pan?
A water heater pan or water heater drain pan is a shallow round or square container that rests under a water heater. The purpose of the drain pan is to collect any leaks from the water heater as well as any runoff or water release from the temperature and pressure relief valve (the T&P valve) on the appliance. A fitting installs in the wall of the pan to connect a pipe that runs to a drain. If the pan fills, the water will run through the pipe and into the drain.
Without a drip pan for the water heater, water could damage the walls, flooring, subfloor, and, if your water heater is on an upper level, the ceiling and walls below. Building codes in your area may require a water heater pan, but even if they don’t, including one with a water heater installation is a good idea to protect against water damage.
You may hear these drain pans referred to as drip pans for water heaters.
You can find drain pans for both tank and tankless water heaters.
Choosing the Right Water Heater Pan
You need to know your water heater type and size and you must be familiar with your local building codes to choose the right water heater pan for your home. We’ve got some tips below, but make sure the water heater pan, fitting and drain system are all in compliance with your local codes.
Water Heater Pan Type
There are several types of water heater pans made of different materials:
If your local building code requires a pan for your water heater, the code will likely specify the type of pan you need based on the water heater type. For example, a plastic or metal pan will often be suitable for an electric water heater. However, if you have a gas water heater, you may need a metal pan.
Water Heater Pan Size
Determine the diameter of your water heater to find the correct drain pan size. The appliance specifications or the manual should list the diameter. You can also simply measure across the top of the water heater. You’ll want a pan with a diameter at least two inches larger than that of the water heater, but be sure the T&P relief valve is within the diameter of the pan. And, of course, there must be enough space on the floor to fit the pan.
Water Heater Pan Drain Fittings
You’ll typically need a fitting to connect a drain pan to a pipe that runs to a drain. Your building code may specify the type of fitting. Polyvinyl chloride (PVC) fittings are common, but some codes may require a chlorinated polyvinyl chloride (CPVC) fitting instead. Some pans come with a fitting while others don’t include the part, allowing you to choose one that’s correct for the code in your area.
The drain pipe is not part of the water heater pan. Your installer should install the pipe and run it to an appropriate drain as a part of the water heater installation.
Water in a Water Heater Drain Pan
Check the water heater drain pan periodically to ensure there’s no water in the pan. Water indicates a problem with the water heater or the pipes or valves connected to the appliance. Call a plumber to diagnose and fix the issue.