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.
Water Heater Temperature Recommendations
120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting.
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 maximum Department of Energy recommended water heater temperature setting you should never exceed is 140 degrees Fahrenheit. The lowest recommended setting should never be below 120 degrees Fahrenheit.
What's the Optimal Hot Water Heater Temperature? Most hot water heaters are set at the factory setting of 140 degrees Fahrenheit, but this isn't necessarily the best temperature for it. The United States Department of Energy recommends that most people set the temperature at 120 degrees Fahrenheit.
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.
And while there is a very slight risk of promoting legionellae bacteria when hot water tanks are maintained at 120ºF, this level is still considered safe for the majority of the population. If you have a suppressed immune system or chronic respiratory disease, you may consider keeping your hot water tank at 140ºF.
In general, this balance is best struck when your water heater is set to about 120°F (49°C). This temperature is hot enough to meet your daily needs, including a relaxing shower or a steaming hot cup of tea, while also being energy-efficient and safe.
According to most dermatologists, the ideal shower temperature is anywhere between 98°F (37°C) and 104°F (40°C)—and no more than 105 °F (41°C). Rinsing under lukewarm water allows you to stay comfortable and maintain your body temperature while reaping all the benefits of both hot and cold showers.
Though the DOE says you can save money on hot water by lowering the maximum temperature of your water heater from 140° F to 120° F, we don't necessarily recommend it. That's because the lower temperature might invite opportunistic bacteria—including Legionella, associated with Legionnaires' disease—to proliferate.
What Temperature Should a Water Heater Be Set At? Most water heaters are designed to operate safely at temperatures between 120 and 160 degrees. Many tank-style units also have a low-temperature setting where the unit will only heat up the water to around 90 to 100 degrees.
Most homeowners should flush their water heaters every 6 months or so, but if you have extremely hard water, you may want to do it more often. Flushing your hot water heater could be necessary as often as every few months depending on the mineral content of your local water supply.
Raising the temperature setting on your water heater ultimately makes your hot water supply last longer. It will ensure everyone gets a hot shower, with plenty leftover to run your dishwasher and washing machine.
Yes, it's very bad to turn your water heater all the way up. To do so will reduce its life, increase your electricity bill and could possibly cause scalding—particularly if you have young children or an elderly relative living in your home.
The lower the temperature, the greater the safety and savings in energy cost. To achieve this, we recommend a temperature setting of 120°F or less. Water temperatures over 125°F can cause severe burns instantly or death from scalds.
The U.S. Consumer Product Safety Commission (CPSC) urges all users to lower their water heaters to 120 degrees Fahrenheit. In addition to preventing accidents, this decrease in temperature will conserve energy and save money.
The primary way most people notice their water heaters overheating is because the water becomes unbearably hot, scaldingly so. If your water heater is set on too high a temperature, burns, and severe injuries may occur.
If you have a low-flow showerhead installed, you can expect to use about two gallons of water per minute, equalling 20 gallons throughout a 10-minute shower. With a standard showerhead, around half a gallon more water will emerge each minute, so a 10-minute shower would use somewhere close to 25 gallons.
So, What Is the Ideal Shower Temperature? “Luke warm,” says Anolik. Many experts agree the tepid temperature feels slightly warm compared to your body temperature, and falls somewhere between 98º and 105º F.
For that reason, other agencies like the Occupational Safety and Health Administration (OSHA) recommend a water heater temperature of 140 degrees Fahrenheit. If everyone in your home has a strong immune system, 120 degrees should be considered safe, but it's also the minimum.
General Recommended Water Heater Temperature
If you go to the Environmental Protection Agency, you'll receive a recommended water temperature of 120 degrees Fahrenheit.
120 Degrees is the recommended max temperature for water heaters, according to both the American Society of Sanitary Engineering and the US Department of Energy. Firstly, setting the max temperature to 120 degrees prevents the water from scalding your skin.
We recommend always keeping the heater set between 110 and 120 degrees. In the summer, try setting your water heater temperature at the low end of this scale, placing it close to or at 110 degrees.
Many kayak anglers follow the 120 rule. This rule states (in Fahrenheit) that the air temperature plus water temperature should be greater than or equal to 120. With the caveat that water temperatures should be at or greater than 60 F.
So, the solution that many people recommend is to set the water at 125 degrees F. This is certainly hot enough to burn an older person or a young child.