What is the minimum temperature for hot water in plumbing systems?

The minimum temperature for hot water in plumbing systems is established to ensure both safety and functionality. At 120 degrees Fahrenheit, hot water is hot enough to effectively prevent bacterial growth, particularly the bacteria that cause Legionnaires' disease. This temperature is also considered safe for most household activities, such as bathing and dishwashing, while minimizing the risk of scalding for users.

Water at temperatures below this level may not adequately serve the intended purposes, such as sanitizing dishes or clothing during washing, as well as providing an appropriate temperature for bathing without the risk of harmful microbes. Temperatures above this level, while effective for disinfection, may pose a higher risk of scalding, especially for children and the elderly. Therefore, 120 degrees Fahrenheit strikes a balance between safety and effectiveness in a residential plumbing system.

In comparison, the other temperature options, while they may seem adequate for certain uses, do not meet the standard that balances efficacy and safety as well as 120 degrees Fahrenheit does.