Dishwasher - Correct Water Temperature
For proper cleaning performance and to prevent damage to dishes, water entering the dishwasher must be at least 120 degrees Fahrenheit and not more than 150 degrees Fahrenheit. Always make sure the dishwasher is connected to the hot water line, not the cold water line. A dishwasher cannot be connected to a cold water supply line because the dishwasher is not able to heat cold water to the required 120 degrees Fahrenheit temperature.
You can check the water temperature going into the dishwasher using a candy or meat thermometer. Turn on the hot water 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 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 to achieve a good wash and dry performance.