True or false: During a large hospital's peak hot water demand, Legionella bacteria in water entering a primary water heater set at 60 degrees Celsius will likely die before exiting the water heater.

The assertion is false because Legionella bacteria are relatively resilient, and simply passing through a water heater set at 60 degrees Celsius does not guarantee their destruction. While 60 degrees Celsius (140 degrees Fahrenheit) is generally considered a temperature that can inhibit the growth of the bacteria and is effective in reducing their numbers, it is important to note that exposure time is crucial for thermal inactivation. Bacteria may not be exposed to this temperature for a sufficiently long period during peak demand, leading to the possibility that not all Legionella will be killed before exiting the heater.

In addition, the water heating and distribution system dynamics, such as flow rates and retention times, play a significant role in the efficacy of thermal disinfection. Rapid water flow during peak demand might not provide enough dwell time for the water to remain at the necessary temperature for complete inactivation.

Thus, while 60 degrees Celsius is an important temperature parameter in Legionella management, it is not definitive enough by itself to ensure that all bacteria will die before the water exits the heater during peak conditions.