Australia’s Plumbing Code dictates that hot water system temperature must be kept at no less than 60 degrees Celsius.

This will prevent the growth of Legionella and other types of bacteria. This rule applies to all water systems including solar, electric, gas and heat pump systems.

Justification for This Rule

Legionnaires disease can result from the Legionella bacteria. It is essentially a chronic form of pneumonia that is especially dangerous for individuals who smoke. It can also severely impact individuals with chronic illness, those over 50 and individuals with weakened immune systems.

tempering valve with a blue plastic cap

tempering valve

Tempering Device

At this temperature, the water is perfect for storing; however, if the hot water is being delivered to the taps in your home at 60 degrees Celsius, this poses severe risk of scalding. To escape the type of danger the water temperature poses, it is recommended that a tempering valve be installed on the water pipe at feeding areas around the home.

In fact, it is a requirement for all new and replacement systems. The device can be identified by an orange, blue, black and green plastic cap affixed to the piping system.


The purpose of the tempering valve is to ensure the water coming through the hot tap in the bath, vanity or shower is never higher than 50 degrees Celsius. This temperature is adequate for domestic hygiene purposes and it lowers the threat of scalding-related injuries.


There is an exception to this rule when it comes to facilities like early childhood centres, nursing homes, secondary schools and primary schools. In these types of facilities, a thermostatic mixing valve has to be installed to ensure the temperature is no more than 45 degree Celsius.

It should be noted that areas used to carry out personal hygiene activities like the bathroom, kitchen and laundry room could benefit from the 60-degree temperature for the operation of the washing machine, dishwasher and other similar appliances.

Plumbing Maintenance on Kitchen Tap

Hire a Professional

To make sure the hot water system temperature in your home is safely set in both the taps and the hot water system, you should ask a qualified and experienced plumber to check the temperatures of your system and install a tempering valve, if necessary.

History – Hot Water System Requirement

In the past, there were mandatory requirements for energy efficient hot water systems to be installed in all new houses. In addition, this requirement was applied when a hot water system had to be replaced on existing properties in gas reticulated areas. This rule was applied to all systems whether solar, gas or heat pump.

On February 1, 2013, these requirements were repealed. As such, homeowners now have the option of choosing a hot water system that is best suited to their individual circumstances; this includes an electric system, which was unheard of in the past.

For more information about hot water system temperature and other plumbing services, contact us today.