Dishwasher Correct Water Temperature
For optimal cleaning performance and to prevent damage to dishes, water entering the dishwasher must be at least 120 degrees F and not more than 150 degrees F. Always make sure the dishwasher is connected to the hot water line, not the cold.
You can check your water temperature with a candy or meat thermometer: Turn on the faucet nearest the dishwasher, place the thermometer in a glass, and let the water run into the glass until the temperature stops rising (one minute or more).
If the water is not hot enough, your water heater may need to be adjusted. If you have a mechanical (knob) control dishwasher or your water heater is far from the dishwasher, it is a good idea to let the water run in the sink until it gets hot before starting the dishwasher. This makes sure the dishwasher is starting out with the hot water it needs for good wash and dry performance.