Best Temperature for Your Hot Water Heater? | Joyce Heating Inc. (2025)

FAQs

Best Temperature for Your Hot Water Heater? | Joyce Heating Inc.? ›

120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting.

At Green Energy Mechanical, we typically recommend to our customers that they set their water heater to between 130 and 140 degrees. The only exception is if you have small children at home. In this case, you should always leave your unit set to 120 degrees to prevent your kids from accidentally being scalded.

The standard temperature for most water heaters is 140 degrees F, but the Department of Energy recommends turning down the temperature to 120 degrees to save energy.

The American Society of Sanitary Engineering recommends that hot water tanks be set from 135 to 140 degrees, to inhibit the growth of Legionella bacteria, with the installation of anti-scald devices and tempering valves to prevent hot water injuries.

For safety, turn off the power to your water heater before doing any work to the unit. On a gas water heater, the temperature gauge doesn't have numbers – it's labeled “Hot” and “Warm” with a few lines in between. The warm setting should be between 90-110° degrees, while the hot setting should be 140-150°.

Although some manufacturers set water heater thermostats at 140ºF, most households usually only require them to be set at 120ºF, which also slows mineral buildup and corrosion in your water heater and pipes. Water heated at 140ºF also poses a safety hazard—scalding.

If you place your water heater on a higher setting, the water coming out of it will be hotter, and you won't need as much to reach that same temperature. Raising the temperature setting on your water heater ultimately makes your hot water supply last longer.

Set the temperature too low, and you could turn your water heater into a breeding ground for dangerous bacteria. Set it too high, and you could be setting yourself up for a scalding accident. How Low Can You Go? The short answer: 120 degrees Fahrenheit.

Even though most units will go up to 160 degrees, you really shouldn't ever set the temperature higher than 140 degrees in order to reduce the risk of scalding. The EPA recommendation is to always leave your water heater set to 120 degrees.

The best temperature setting for a hot water heater is between 120 and 140 degrees. Below 120 degrees, bacteria can develop in the stagnant water sitting in the tank. Above 140 degrees, the water is so hot that you and your family members can be at risk for scalding in as little as two seconds.

What is the safe setting for a hot water heater? ›

120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting. Most experts agree that anything below 120 degrees creates a risk for bacteria to develop inside your water heater from stagnant water, such as legionella that causes Legionnaire's disease.

However, during the warmer months, you don't need the water to be as hot, and a lower temperature setting can save you energy and money. Set the temperature to around 120 degrees Fahrenheit. Drain and flush the tank: Over time, sediment can build up in the tank, which can reduce its efficiency and lifespan.

That means “A” is 130 degrees, “B” is 140, and so forth. The “Very Hot” setting is typically 160 degrees, and there is no reason to ever set the unit this high. Some water heaters also have a Vacation setting. When set to Vacation mode, the unit won't heat at all to prevent energy waste.

According to Centers for Disease Control and Prevention (CDC), water temperatures ranging from 130 to 140 degrees Fahrenheit(°F) can eliminate most of the harmful bacteria. However, be warned that these high temperatures can also increase the risk of scalding.

A water temperature of 120°F does not kill the Legionella bacteria; a hot water temperature of 140°F is required at which Legionellae dies in 32 minutes. Hence it is recommended that the water heater be set at a safe hot water temperature of 140°F.

The best temperature setting for a hot water heater is between 120 and 140 degrees. Below 120 degrees, bacteria can develop in the stagnant water sitting in the tank. Above 140 degrees, the water is so hot that you and your family members can be at risk for scalding in as little as two seconds.

The EPA recommendation is to always leave your water heater set to 120 degrees. This is both so that the unit loses less energy and also to prevent possible scalding. OSHA, on the other hand, recommends setting your water heater to 140 degrees in order to aid with cleaning and sanitation.