It's not that uncommon to find the dishwasher drain line not properly looped. I find them on almost every home inspection I perform and the most frustrating thing is that it's very simple to get it right the first time the dishwasher is installed.
What could happen if the dishwasher drain is not properly looped? Improperly installed drain line could lead to water back-flow into the dishwasher and/or improper drainage of water. Though dishwashers come from the factory with the drain looped up high against the side of the dishwasher, it's still highly recommended to have a high loop under the kitchen sink. So check your dishwasher drain line and high loop it if you need to, your clean dishes will thank you later.
