What is the maximum domestic hot water temperature the building should deliver?

• A. 140 degrees F
• B. 120 degrees F
• C. 110 degrees F
• D. 130 degrees F

Answer: (B)

Delivering hot water at a safe, workable temperature is about preventing burns while still providing usable hot water. The standard maximum at the point of use is 120°F because it minimizes the risk of scald injuries for all occupants, especially children and the elderly, while still being hot enough for typical tasks like showering and washing hands. Using higher temperatures (like 130°F or 140°F) at the taps would increase the chance of burns even with brief contact. A lower temperature (such as 110°F) would be insufficient for comfortable bathing and cleaning in many situations. If the storage temperature is higher for disinfection purposes, a mixing or tempering valve can be used so the water delivered to fixtures does not exceed 120°F. That combination keeps safety and practicality in balance, making 120°F the appropriate maximum delivered temperature.