What is the highest temperature tap water allowed inside a house?

The highest temperature tap water allowed inside a house is 120°F. This temperature is considered safe for household use, particularly for preventing scalding burns. Water at 120°F minimizes the risk of burns for most adults, while still being hot enough for effective cleaning and sanitation purposes.

At temperatures higher than this, the risk of burns increases significantly. For instance, water at 140°F can cause severe burns in just a few seconds, especially for children and the elderly, who are more vulnerable to scald injuries. The 120°F standard accounts for a balance between safety and functionality, making it the ideal choice for household tap water temperature.