Legionnaires Disease

Legionnaires disease is an infection of the lung caused by the Legionella bacteria.  The bacteria causes a form of pneumonia that can be fatal.   

The disease is caused by breathing in aerosols which contain Legionella bacteria.  This bacteria is present in low levels in the environment, but can grow to dangerous levels in cooling towers and in warm water systems. 

Legionella growth can be controlled by proper water treatment procedures and regular cleaning.  

Additional information on Legionnaires Disease can be found on the NSW Health website – Legionnaires Disease Factsheet  

Building Owners and Occupiers 

Building owners and occupiers have the prime responsibility to properly install and maintain all water-cooling systems, air-handling systems, and hot and warm-water systems.  These systems are known as “regulated systems” because they are regulated by the Public Health Act 2010 and the Public Health Regulation 2012.  

 Examples include: 

  ·    Water cooling towers  (for air conditioning or industrial applications)
  ·    Evaporative coolers (attached  to non-residential premises)
  ·    Humidifying systems (for agricultural or industrial applications)

  ·    Warm water systems (including but not limited to thermostatic mixing valves in hospitals) 

The proper installation, maintenance and cleaning of systems is a legal requirement.  Building occupiers who fail to meet these requirements are liable to heavy fines or even imprisonment.  Systems can be inspected at any time. Additional information on Legionnaires Disease can be found on the NSW Health website – LegionnairesDisease Control for Building Owners and Occupiers Factsheet  

Servicing and Water Treatment 

All water-cooling systems can only be operated if they are equipped with a process designed to control microbial growth certified annually by a competent person and only if the process is in continuous operation. 


Only “duly qualified” contractors can be engaged to install, operate and maintain regulated systems.  The Office of Fair Trading licenses contractors who undertake this work.

All regulated systems are required to be equipped with an operating and maintenance manual.  The manuals must include all details of inspections and servicing performed.  Manuals and records must be kept on site.  

Removing a Water-Cooling System 

If a cooling tower or water-cooling system is no longer in operation on your site, it must be decommissioned by a licensed contractor.  Once this has been actioned your contractor should give you a Decommissioning Certificate.  You must then submit to Council as soon as possible so that the system can be removed from the Register of Regulated Systems.  

Council Registers 

Local councils are required to keep a register of water-cooling systems, and hospital warm-water systems installed on premises in their area.  

It is the occupier’s responsibility to ensure that council is provided with the necessary information.  Council’s Register of Regulated Systems must contain the following information: 

  ·    the address and telephone number of the premises on which the system is installed,
  ·    the name and contact details of the occupier of the premises (including residential address, e-mail address and      home, business and mobile telephone numbers), 
  ·    the Australian Business Number (ABN) or Australian Company Number (ACN) (if any) of the occupier of the      premises, and 

  ·    the type of regulated system (including make, model and serial number).  

Records to be submitted to Council 

A copy of the annual certificate of disinfection is to be submitted to Council.  Similarly a copy of all records of service and cleaning are to be submitted to Council.  Council officers will inspect and record all information submitted in the Register of Regulated Systems and may undertake individual site inspections. 

Additional Information

For further information refer to NSW Health website – Legionella and Legionnaires Disease 
NSW Public Health Act 2010 – Legionella Control             
NSW Public Health Regulation 2012 – Legionella Control           


Warm-water system – Registration Form 

Water-cooling system – Registration Form