Booster water heaters are not necessary but depending on the temperature of your dishwasher, your establishment may need one. For low-temperature dishwashers, you will not need a booster water heater if it runs at 120 degrees Fahrenheit. For high-temperature dishwashers, you will not need a booster water heater if your machine runs at 180 degrees Fahrenheit. A booster water heater will allow your rinse cycle water to reach the required temperature to properly sanitize your wares.