Dishwashers do not sterilize the utensils, as proper sterilization requires autoclaving at 121 °C with pressurized wet steam for at least 15 minutes. Commercial dishwashers can use one of two types of sanitizing methods: hot water sanitizing (using final rinse water at a temperature of at least 83 °C (180 °F)), or chemical sanitizing (by injecting chlorine in the final rinse water). Not all dishwashers are capable of reaching the high temperature required for hot water sanitizing. Medical grade dishwashers and sanitizers are starting to use ultrasonic cleaners, which use a liquid bath treated with sonics to remove particles and sterilize instruments.

Most consumer dishwashers use a 75°C thermostat in the sanitizing process. During the final rinse cycle, the heating element and wash pump are turned on, and the cycle timer (electronic or electromechanical) is stopped until the thermostat is tripped. At this point, the cycle timer resumes and will generally trigger a drain cycle within a few timer increments.

Most consumer dishwashers use 75°C rather than 83°C for reasons of burn risk, energy consumption, total cycle time, and possible damage to plastic items placed inside the dishwasher. With new advances in detergents, lower water temperatures (50-55°C) are needed to prevent premature decay of the enzymes used to eat the grease and other build-ups on the dishes. This also saves energy and can allow the washer to be hooked directly to the hot water supply for the house.

In the US, residential dishwashers can be certified to a NSF International testing protocol which verifies the cleaning and sanitation performance of the unit.