Heated water

The health and safety of the public is important.  Avoid the likelihood of growth of Legionella and other bacteria in your heated water system and make sure the temperature is set to the right temperature.

New system - house

  • You do not need a plumbing permit to replace a hot water system as long as the model is like-for-like, in the same location and connected to drinking water.
  • You do need a licenced plumber to do the work.
  • You will need a licensed plumber to put in a new hot water system if it is in a new location and connected to an existing service.
  • Your plumber will need to notify the Permit Authority after the work is completed.
  • You will need a licensed plumber to put in a new hot water system in a new location with a new service.
  • You will need a plumbing permit from the Permit Authority before you can begin work.

Repair and maintenance

All maintenance and repairs for hot water systems must be done by a licensed plumber.

Heated water temperature

Both risks are potentially life threatening, and both can be addressed by complying with the following requirements

  • A tempering valve device must be installed and set to deliver water to sanitary fixture outlets such as showers, baths, basins, bidettes and bidets and must be set to 50 ºC; and
  • For early childhood centres, primary and secondary schools, and nursing homes or similar facilities for the young, aged, sick or disabled persons, a thermostatic mixing valve must be installed and set to 45ºC.
  • The temperature setting for stored heated water must not be less than 60ºC to kill off Legionella or other bacteria.

Technical information

There are two key safety problems around heated water temperature:

  • risk of scalding from heated water
  • risk of bacteria incubating in water which is not hot enough to kill them.

It is not a mandatory requirement to supply tempered water (at 50 ºC) to a kitchen sink or laundry trough/washing machine taps.

A thermostatic mixing valve may be substituted for a tempering valve but where installations require a thermostatic mixing valve (see above) a tempering valve must not be substituted / installed.

Point of use heated water heaters must be designed and set to deliver heated water no hotter than 50ºC.

You will find more information in the Director’s Determination – categories of plumbing work.

You will find more information in Australian/New Zealand Standard, AS/NZS 3500.4:2015 Plumbing and drainage Heated water services (Part 4) (external link).

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Updated: 16 Aug 2022

This page has been produced and published by the Consumer Building and Occupational Services Division of the Department of Justice. Although every care has been taken in production, no responsibility is accepted for the accuracy, completeness, or relevance to the user's purpose of the information. Those using it for whatever purpose are advised to verify it with the relevant government department, local government body or other source and to obtain any appropriate professional advice. The Crown, its officers, employees and agents do not accept liability however arising, including liability for negligence, for any loss resulting from the use of or reliance upon the information and/or reliance on its availability at any time.