What is the minimum depth required for a drain pan beneath a water heater?

The minimum depth required for a drain pan beneath a water heater is 1 1/2 inches. This depth is specified in plumbing codes to ensure that any potential leaks or spills from the water heater can be effectively contained and directed to a drain. A depth of 1 1/2 inches provides enough capacity to hold any significant amount of water that might escape, thus preventing water damage to the surrounding area.

In many codes and standards, such as those from the International Residential Code or local plumbing regulations, the dimensions of drainage pans are established to ensure safety and reliability in plumbing systems. A shallower pan might not accommodate the potential volume of water from a significant leak, defeating the purpose of having a drain pan altogether. This code requirement underscores the importance of preventative measures in maintaining plumbing systems and protecting property from water damage.