What Is The Best Temperature For My Water Heater?

by Jay | Posted on July 21st, 2022

Temperatures for electric, gas and tankless water heaters are typically preset at the manufacturing. The good thing is that you can change them to fit your needs in minutes.

However, you should be aware that setting your water heater’s temperature too high might have serious effects, such as scorching. In addition to scalding burns, greater water heater temperatures will result in rising power expenditures.

water heater temperature

Lowering the temperature to particular levels, on the other hand, can result in the growth of bacteria and, eventually, infection. Therefore, the most important thing is to maintain a temperature that is neither too hot nor too cold. Below, we offer advice on how to strike this balance to determine the ideal temperature for a water heater.

Factors That Affect Hot Water Temperature Setting

You might consider how you should determine the perfect water temperature setting for several reasons.

These variables are unaffected by the type of piping you have (PEX, PVC, or copper), how the water is heated (gas or electric), or even whether you have a tankless water heater.

  1. If you have a dishwasher that does not pre-heat the water, you should set your water heater to 140 degrees.
  2. Those elderly or have tiny children may want to keep the temperature at 120 degrees. It only takes two seconds for a child to acquire third-degree burns from water that is 150 degrees, and five seconds if it is 140 degrees, the temperatures at which water heaters frequently leave the factory.
  3. Homes with residents who have a compromised immune system or respiratory problems should keep the hot water temperature at 140°F.
  4. In general, many people who live alone strive for a lower temperature in the permissible range because there is less demand for hot water, and it saves money. On the other hand, many people who live in large households aim for a higher temperature to meet the increased demand for hot water.
  5. If you want to save money, dial the water tank thermometer by 10 degrees to save 3 to 5 percent on your energy cost.
  6. Are you still undecided? Set it to 120 degrees and gradually increase the temperature until you find the ideal shower temperature.

What Temperature Should Your Water Heater Be Set to?

The Consumer Product Safety Commission (CPSC) recommends keeping the water heater temperature above 120 degrees Fahrenheit (49 degrees Celsius) to avoid scorching. Not to mention that a water heater set too high will unnecessarily boost your electricity cost. But, of course, each home is unique.

Best Water Heater Temperature

The temperature of your water heater should be between 123° and 140° Fahrenheit. Setting the temperature dial to the lower end of this range will save you money by lowering the energy necessary to heat your water. On the other hand, those who like to take particularly hot showers or are concerned about bacterial growth prefer higher temperatures.

Water Heater Recommendations by OSHA vs. EPA

According to OSHA, water heater temperatures should be set at 140 degrees. They also indicate that water should reach the farthest faucet, shower, or other water appliance when the temperature is over 122° F. This prevents Legionella pneumophila from growing in an environment that promotes its growth.

Water polluted with L pneumophila can and has resulted in lethal pneumonia outbreaks. Setting your water heater to 140° F reduces the potential for developing germs like L pneumophila. However, as previously said, it increases the risk of being burned by scalding hot water.

The Environmental Protection Agency (EPA) recommends 120 degrees to reduce power use. In addition, they claim that lowering your water temperature to this level can save you up to $461 yearly. But, of course, it is up to you and your family to decide which temperature to set between 123° and 140° Fahrenheit.

How Do You Determine the Ideal Temperature for Your Water Heater?

If you have little children, it may be advisable to err on the low end of the suggested water heater temperature range. This method reduces the possibility of an unintentional burn.

On the other hand, if you want to prioritize a clean and well-sanitized home, you can raise the temperature of your water heater to around 140 degrees. This is an excellent option for households with immune-compromised family members.

So, after all of this conversation, you still don’t know the ideal temperature for your water heater. Setting your water heater to 130 degrees Fahrenheit may give the ideal balance. The water will be hot enough for sanitation but not hot enough to cause burns in the family.

Is 120-degree water hot?

The EPA recommends 120 degrees because it is hot enough to keep diseases away but not hot enough to cause scorching, provides enough hot water for most small families, and is relatively energy-efficient. However, depending on a few criteria, your optimum setting may differ.

Is 140 too hot for a water heater?

Professionals recommend keeping your water heater set between 130 and 140 degrees Fahrenheit. Any higher or lower value could endanger you and your family. While raising the temperature can result in burns, lowering it below the recommended setting can also be hazardous.

Can 140 degrees burn you?

Most adults will suffer third-degree burns when exposed to 150° water for two seconds. Burns can also occur after a six-second exposure to 140° water or the thirty-second exposure to 130° water. Even at 120 degrees, a five-minute exposure could result in third-degree burns.

Will 120-degree water kill bacteria?

Keeping your water heater in this temperature range for an extended period will result in a massive buildup of bacteria. The bacteria, however, stop growing above 120°F. This temperature, however, will not kill the bacterium; rather, it will hinder it.

If you are concerned about bacteria and pathogens

Consider a hot water tank booster if you are concerned about germs in your hot water and scalding water. This retains your water at 140°F in the tank but mixes it with cold water to reduce the temperature to 120°F before it reaches the tap.

If you live in a large house where hot water takes a long time to reach the tap, a hot water circulating system can help. This method circulates hot water slowly through the pipes to keep it from chilling before it reaches the tap.

The temperature of Legionella Water

Approximately 100 Americans are hospitalized yearly due to bacterial infections from water heaters. In addition, legionella pneumophila, as previously established, can cause Legionnaire’s disease and Pontiac fever.

When bacteria-containing droplets are inhaled, Legionella affects the immune system via the respiratory tract. This could happen due to anything as easy as taking a shower. Smokers (or former smokers), the elderly, anyone with a chronic lung condition, or anyone with a damaged immune system is most at risk.

Like other types of bacteria, Legionella bacteria grow in stagnant water below 122 degrees Fahrenheit. As a result, keeping your water at a high enough temperature helps to inhibit the growth of these bacteria while lowering your risk of Legionnaire’s disease.

How to Check the Temperature of a Water Heater

Most water heaters on the market today do not have a temperature gauge. Instead, they have a thermostat that solely shows heating temperature ranges.

A kitchen thermometer and a cup are all required to determine the water heater’s temperature.

  • Allow your water heater to sit idle for at least one hour for best results.
  • After 60 minutes, turn on any faucet near the water heater.
  • Allow water to flow for at least one minute while ensuring it is at its warmest.
  • Allow it to fill the cup before inserting a thermometer.
  • Temperatures can be adjusted as needed.

Please remember that before using your thermometer, we recommend immersing it in icy water until it reaches 32 degrees (or its lowest setting). This procedure assists in resetting the thermometer so that your measurement is as accurate as possible.

Changing the Temperature of a Water Heater

If your water heater is not supplying water at the desired temperature, you just need to adjust it. But, again, you’ll probably simply need a socket, a tiny wrench, and a screwdriver.

As a reminder, most models have the temperature set by the manufacturer. Only deviate from this setting until you’re acquainted with the merits and cons, such as those listed above.

How to Change the Temperature of an Electric Water Heater

First, cut off any electricity to the unit, usually done at the circuit breaker. Next, figure out where your thermostats are.

Typically, two thermostats (or one on smaller systems) are located behind an access panel.

  • After that, proceed to remove the required access panel(s).
  • The thermostat adjustment should be located here [perhaps under some insulation].
  • You can then replace the panels and any insulation by adjusting the thermostat control with a screwdriver in the direction of your chosen temperature.
  • If you are uncomfortable with this technique, we recommend reviewing your unit’s manufacturer’s literature or contacting them directly.
  • Finally, reactivate the unit’s power. Wait 2-4 hours for your water heater to acclimate to the new settings before testing the water temperature.

How to Change the Temperature of a Gas Water Heater

Most gas water heaters have a setting knob that you may use to change the temperature to your liking. However, these controls, such as electric units, are sometimes hidden behind an access panel.

Once you’ve found it, you can raise the temperature by turning the knob to the ‘hot’ position and vice versa.

Just as you would with an electric unit, wait a few hours before testing the temperature. If your heater has a ‘vacation’ option, it will not heat water.

How to Change the Temperature of a Tankless Water Heater

Most tankless water heaters have an easily accessible LED display where you may change the temperature setting.

If you have a POU (point of use) tankless water heater, you can confidently choose a temperature setting on the lower end of the spectrum.

This is because the water travels a shorter distance to the exit point (e.g., a faucet), providing less opportunity for water to cool to the point where bacteria can thrive.

Getting Rid of Hot or Cold Water Spikes

We propose adding a temperature regulator or thermostatic mixing valve to the above temperature recommendations. This will help to keep water temperatures from rising too high or falling too low for safety (scalding) or comfort.

These devices are often connected to the water heater’s outlet. It will then automatically mix hot and cold water, assisting you in obtaining your preferred temperature continuously. This includes addressing hot or cold water spikes prevalent in the shower and produced by a nearby toilet flush, washing machine, or dishwasher.

Most temperature regulators are designed to work with all types of water heaters on the market. A good quality thermostatic mixing valve can cost up to $150, but we offer a cheaper one from Amazon for around half the price.

We hope you found this information useful, but if you have any more questions or would like a second opinion, we recommend contacting the maker of your water heater or a specialist.


Jay is a health and wellness enthusiast with expertise in water quality and nutrition. As a knowledgeable advocate for holistic well-being, Jay successfully manages Type 2 Diabetes through informed lifestyle choices. Committed to sharing reliable and authoritative insights, Jay combines firsthand experience with a passion for enhancing health."