A water heater drain pan should be equipped with at least what size drain?

A water heater drain pan is designed to catch any potential leaks or overflow from the water heater, helping to prevent water damage. The correct size for the drain should ensure that any water that collects in the pan can be efficiently and effectively removed. A drain size of at least 3/4 inch is appropriate because it provides enough capacity to handle the potential volume of water in a reasonable time frame while also accommodating the size of the fittings and piping typically used in plumbing systems.

Using a drain that is smaller, such as 1/2 inch, might lead to drainage issues if a significant amount of water were to accumulate, since it may not allow for quick enough drainage, increasing the risk of spilling over. Similarly, larger sizes like 1 inch or 1-1/2 inch are generally unnecessary for this application, as they may complicate the drainage setup without significant benefits compared to the standard 3/4 inch option. Thus, the 3/4 inch drain strikes a good balance between efficiency and practicality for a water heater drain pan.