Rinsing your dishes beforehand not only wastes water but also won’t get your dishes as clean. (We aren’t saying to put dishes in with heaping globs of ketchup on them, and you certainly don’t want to put them in if the condiment grime has set on the dish overnight. This just pertains to fresh food messes that are going into the dishwasher right away.)

Source: https://www.buzzfeed.com/kristatorres/how-to-load-a-dishwasher