One of the most common plumbing mistakes in a home is the lack of the air gap or drain loop by the dishwasher.
That lets kitchen sink waste water to enter the dishwasher, so you won’t want to wash your dishes with dirty water.
This is how the air gap works:
The air gap is usually located right by your kitchen faucet.
The water discharge from to dishwasher, and goes up in a loop in the air gap and falls down in the sink trap.
The air gap should not leak, but it is normal to hear gurgling as the water goes through the loop.
If you don’t have a air gap you would want to look underneath your sink to make sure you have a loop on your drain hose. Your dishwasher drain hose needs to be higher than the sink drain.
The drain hose that goes from your dishwasher to the drain pipe or garbage disposal should have a loop and be mounted higher than the sink. Very often the drain hose goes in a slop from the dishwasher to the drain pipe, that is an improper way and you will very likely get kitchen waste water in your dishwasher.
If you still are having problems with dirty dishes there is a couple of other simple things you can try:
1. Run your kitchen sink on hot water until the water that comes out of the faucet is really hot, then start the dishwasher.
Think of when you start to run your faucet on hot, it usually doesn’t come out as very hot right away. That is the same for the dishwasher as well. Doing this prevents cold water from entering the dishwasher, and as you know cold water does not do as good as hot water when it comes to cleaning.
2. Try to change your soap.