Safe Water Heater Temperature – What Temperature Should You Set?

The appropriate temperature must ensure while doing a shower. There is nothing worse than getting scald in the shower because of the high water temperature. Many diseases occur due to stagnant water like legionnaires disease it is one type of pneumonia. A user of water heater should be aware of the Safe Water Heater Temperature in their home. If a user sets right temperature in the house according to a situation like doing shower, washing things, seasonal demand and many more.

Water heater - Issue of Goldilocks

In the segment there are two primary and opposing risks:

  • If the temperature of the water heater is too high then in many cases a person may get scalded.
  • The low temperature of the water heater may develop the risk of pathogens particularly a disease called Legionnaires.

Problems with minimum temperature

There is a research paper called Legionella and its way of prevention found on the website of the World Health Organization. In that paper, it showed the details of the temperature in water and the effect of the survival of Legionella.

Summary of the research paper

  1. Legionella bacteria dies instantly when the temperature is above 70 degree Celsius (158 degrees Fahrenheit).
  2. With 60 degree Celsius or 140 degrees Fahrenheit, 90% of the disease bacteria die within minutes.
  3. At 48 to 50 degree Celsius (118 to 122 degree Fahrenheit), the bacteria disease survives but cannot multiply.
  4. The disease grows quite effectively when the temperature is around 32 to 42 degree Celsius (90 to 108 degree Fahrenheit).

Dishwasher temperature to be set at

There are many changes in the current models of dishwashers including in the temperature section. In today's model dishwasher have a minimum requirement of 49 degree Celsius (120 degrees Fahrenheit). You will find heaters in most products. Heaters heat the interior according to need. A user checks specifications if they have an older model. There are many dishwasher detergents which vary in the temperature requirement. But it works ideally in between 50 and degree Celsius. Cold water detergent on the market works in any set of temperature required to perform the washing task.

When the temperature s set to a maximum limit?

Scalding happens when the temperature is set very high. When the tap s opened first, the water in the pipe gets a little bit cooler, and the temperature will increase dramatically once the water from the tank reaches to the point for use. Small babies, elderly and children are at risk because of their thin skin. On the other side, older people skin is less sensitive for which they feel the scald damage later. Older people will get many problems because of their slow movement when they find the water is boiling. The Consumer Product Safety Commission (CPSC) suggested setting the temperature in 49 degree Celsius or 120 degrees Fahrenheit. The commission is very experienced in research, and their recommendation is highly reliable.

Dead Legs

Dead legs contain stagnant water. It's the ideal breeding ground for bacteria and contaminates the entire system. Water found in the dead leg gets warm but never gets too much hot. It does not mix with the temperature of the main flow.

Valve needs to e installed in the closed section of the main line. The valve would be no more than one pipe diameter away. Thus, it minimizes the risk of the development of stagnant water and bacteria.

Pipe issue in PEX vs. Copper

In a research study, it has found that Legionella grows faster in PEX than copper. The development occurs for throughout 500 days. Again, within 800 days the growth is stable. Both pipes have similar biofilm formation.

Copper cools down faster than PEX. If there is enough given time, the temperature of both will cool to low.
In some cases, insulation does not work. Even with insulation, water in pipes gets cool in its ambient level.

Some conflicting views

In a debate some experts of the Canadian Commission on Building and Fire Codes (CCBFC) rejected the lower maximum of the hot water tank temperature which is 49 C. By keeping the statement in mind, many trusted organizations are advising the homeowners to low the temperature at 49 C as a precaution against scald comes from the tap. Many people offer tips to find the thermostat, so the user adjusts the issue by them.

Bottom-line view

Water should be stored at a high temperature as prevention from getting bacteria into it. Then, it is to be delivered from the tap at low temperature to prevent scald problem. 


Our team of expert researched many paper and articles. The best way is to install anti-scald mixing valves at each human point like the sinks, tubes, taps and those places where water comes out for use. Whether it is integrated into the shower valve or installed under the sink. The tank is to set to 60 degree Celsius according to the report of World health Organization (WHO). Many scientists and biologist have found the temperature in this view of WHO is a proven fact. In each human point of use, the limit is 49 degree Celsius or 120 degrees Fahrenheit. In kids bathroom, the temperature can be set to low like 110 degrees Fahrenheit. For other use like dishwasher, washing machine, and humidifier the temperature is a bet placed to full 60 degree Celsius. So safe water heater Temperature is the most important factor to prevent the risk of unexpected accident.

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