What is the maximum allowable temperature for hot water in residential plumbing?

The maximum allowable temperature for hot water in residential plumbing is 120°F. This temperature is generally recommended because it balances safety and comfort. Water at this temperature is hot enough to meet the needs for sanitation and proper cleaning while minimizing the risk of scalding, particularly for vulnerable populations such as young children and the elderly.

At temperatures above 120°F, there is a significant increase in the risk of burns, especially if water is inadvertently splashed or if someone accidentally comes into contact with it. Many plumbing codes and guidelines often set this limit to 120°F to promote safety in household settings. Additionally, maintaining hot water at this temperature can help prevent the growth of harmful bacteria, such as Legionella, in the water heater while still being mindful of safe usage practices.