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Legionella, legionellosis and Legionnaires' disease

Legionellosis is a collective term for diseases caused by Legionella bacteria including the most serious, Legionnaires' disease, as well as the less serious condition of Pontiac fever.

The Queensland Government provides guidelines to assist businesses and industry to control Legionella.

Managing workplace risks

At a workplace, Legionella has been found in water linked with the following pieces of equipment:

  • vehicle wash systems
  • horticultural misting systems
  • misting systems in supermarket fruit and vegetable displays
  • emergency showers
  • eyebaths and face-wash fountains
  • sprinkler and hose reel systems
  • air washers
  • wet scrubbers, particle and trivial gas scrubbers
  • industrial process water systems
  • air conditioning and industrial cooling processes
  • potable water systems and spa pools at hotels

Guidelines and resources to help minimise the risk of a Legionella outbreak in some key work environments are referenced below.

Cooling water systems

Guide to Legionella control in cooling water systems, including cooling towers (PDF 200 kB).
Service contractors, designers or owners of cooling water systems should use these guidelines to manage risks associated with Legionella.

Commercial pools and spas

Water Quality Guidelines for Public Aquatic Facilities (PDF 2363 kB)
Provide information for operators of pools, especially those that are used for commercial purposes, about their duty of care obligations to provide a safe swimming environment.

These guidelines are also relevant for businesses such as hotels where swimming or spa pool facilities may be provided.

Accommodation and guest facilities

Commercial operators, such as hotel owners, have a duty to ensure a safe environment for staff and guests. For example, hot water systems, including shower roses, hot water taps, hot water tanks, pipework and the associated fittings, where there may be stagnant or warm water (25-50 degrees Celsius), have the potential to harbour Legionella bacteria.

Refer to the Legionnaires' disease outbreak investigation toolbox provided by the European Centre for Disease Prevention and Control, which provides risk minimisation information for hotels and accommodation operators.


Anyone working in the plumbing industry should be aware of the risks surrounding Legionella bacteria.

Water handling systems and temperature ranges

Legionella bacteria can be found in a variety of water handling systems, at temperatures ranging from 5 to 60 degrees Celsius.

The bacterium generally remains dormant below 20 degrees Celsius, which is commonly the temperature of water in most cold water storage systems, mains cold water and evaporative coolers.

In hot water storage systems for residential buildings, hot water must be heated to a minimum of 60 degrees Celsius to prevent the growth of bacteria such as Legionella, but it should be delivered to taps at a maximum of 50 degrees Celsius to reduce the risk of scalding-related injuries.

Read more about Hot water system requirements

Plumbing standards and guidelines

One of the best ways to protect the public from Legionella is to ensure that all plumbing work complies with relevant plumbing codes and standards.

Health and residential aged care facilities

Read about water risk management legislation for health and residential aged care facilities.

Information for clinicians

Find tools and resources to help clinicians manage the risks around Legionella infection control.

Additional Information

World Health Organisation 2007 - Legionella and the prevention of legionellosis

World Health Organisation 2011 Water safety in buildings (PDF 785kB)

Legionella Ecology - Legionella pneumophila from MicrobeWiki

Training resources - contact us at Email: to find out about relevant online training courses to help with Legionella control and management.

Last updated: 6 September 2019