What is a good standard hot water temperature, primarily for safety reasons?

A standard hot water temperature of 120°F is widely recommended primarily for safety reasons. This temperature effectively minimizes the risk of scalding, particularly for vulnerable populations such as children and the elderly, who may have slower reflexes or impaired skin sensitivity. At 120°F, the chances of receiving a serious burn are significantly reduced, while still being warm enough for most domestic hot water uses, like showers and dishwashing.

Temperatures higher than this, such as 130°F or 140°F, can increase the risk of burns. For instance, at 130°F, it takes just 30 minutes for a scalding burn to occur, and at 140°F, it takes only about 6 seconds for a serious burn to happen. This makes the higher temperature choices less ideal for maintaining safety in a residential setting, despite some applications in commercial settings where higher temperatures may be necessary for sanitation or specific processes. Furthermore, excessively high temperatures can lead to increased energy consumption and costs.

In summary, 120°F strikes a balance between safety and functionality, encouraging its adoption as a standard in residential plumbing design for hot water systems.