The requirement for a drip pan will depend on where in the house the water heater is located. If it is inside the living space of the house or in a non-living space, such as the garage, but at the same floor level as the living space, a drip pan is required. If the water heater is in a non- living space, such as the garage, and the floor it is resting on is below the finished floor of the living space, a drip pan is recommended but not required.