What is the temperature threshold for a hot water system, in degrees Fahrenheit?

The temperature threshold for a hot water system is typically set at 140°F. This temperature is considered sufficient for the effective sanitization of water, which is crucial for killing bacteria such as Legionella, the bacteria responsible for Legionnaires' disease. Water heated to this temperature helps ensure that the system operates efficiently while reducing the risk of scalding when properly mixed with cold water for end use.

Maintaining the temperature at or above this threshold also helps in preventing issues such as stagnant water in the system, which can lead to further contamination and inefficiency. While some systems allow for lower temperatures, such as 120°F or 130°F, these do not offer the same level of bacterial protection and may not satisfy certain code requirements for health and safety.