The ideal temperature setting for a water heater is between 120 and 140 degrees Fahrenheit. The Department of Energy recommends a temperature of 120 degrees Fahrenheit as it is the safety recommendation against scalding. However, some experts suggest that setting the temperature below 120 degrees Fahrenheit creates a risk for bacteria to develop inside the water heater from stagnant water, such as legionella that causes Legionnaire’s disease. On the other hand, setting the temperature above 140 degrees Fahrenheit increases the risk of accidental scalding.

Factors to consider when setting the temperature include the presence of young children or elderly people who are susceptible to burns, an immunocompromised person, a dishwasher that doesn’t preheat, and multi-occupancy due to higher demand on hot water. It is important to note that the type of pipe, how the water is heated (gas or electric), and whether the system is tank or tankless does not affect temperature setting.

To adjust the temperature, locate the thermostat dial on the water heater and use a flathead screwdriver to adjust the temperature as needed. After adjusting the temperature, it is recommended to run a simple test to ensure that the devices own reading is accurate. Open the hot water tap furthest from the water heater and measure the temperature with a thermometer. If it doesnt match the target temperature, adjust the thermostat and try again in two hours.