• You do not need to pre-rinse
• The most powerful jets in a dishwasher shoot upwards from the bottom, so stack the dirtiest items on the lower shelf and the cleaner or more fragile items above. This is also why your bowls, containers and cutlery should face down.
• A full dishwasher dries better than a half-full dishwasher
• A full dishwasher can clean 144 items with roughly 13 litres of water, or anything between eight and 20. According to a study by the University of Bonn, hand washing the same load uses, on average, 100 litres of water.

Quelle: How to properly load a dishwasher: ‚If you pre-rinse it might actually come out dirtier‘