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Legionella Risk Assessment

legionella risk assessment

Work Health Professionals provide Legionella Risk Assessments in Perth.

We advise on water quality, and prevention and control methods for Legionnaires’ Disease.

Rob Graham is working with us to offer this service to our clients in Perth and WA. Rob Graham has over 20 years experience in water risk management in the UK which includes advising companies on managing the risk from legionella bacteria and other water related problems.

What is Legionella?

Legionella are a type of bacteria found naturally in water and soil, and a few types of the bacteria are responsible for causing the serious respiratory disease Legionnaire’s Disease. 

Because legionella bacteria are found naturally all over the world it can be expected that the potential exists for legionella to enter and grow within some domestic, industrial and commercial water systems we generally come into contact with on a daily basis.

Your responsibilities

legionella risk assessment cooling towers

Owners of commercial premises that have cooling towers, spa pools, or warm water systems (such as hospitals and aged care facilities) are required by law to conduct regular maintenance of this equipment to reduce the risk of legionella contamination. This includes regular cleaning and disinfection to prevent legionella growth.

The type of systems that can harbour legionella bacteria include:

  • Water cooling Systems
  • Air Handling Systems (wet)
  • Water Misting  Systems for food or agriculture
  • Hot & Cold Water Systems
  • Drinking Water Fountains
  • Water Features and Decorative Fountains
  • Spas and whirlpool baths
  • Car washes
  • Respiratory therapy equipment
  • Washing and irrigation systems
  • Potting soils and mulch
  • Emergency Showers and Fire Hoses
  • Sprinkler/Irrigation Systems and Hose Reels

What is a legionella risk assessment?

A legionella risk assessment includes a review of the water systems onsite, sampling of the water, basic schematics of the water systems on that site, along with recommended remedial works and a legionella logbook to record on-going maintenance and testing of the water systems.

Staff training

legionella risk assessment

Work Health Professionals also provide in-house training courses for maintenance staff to enable them to identify and manage the risk from Legionella bacteria and to support good water quality control in the future.

Effective water management systems

The effectiveness of a water management system, including water treatment and microbiological control, should be assessed at least monthly.

Cooling towers should be operated and maintained using a risk based approach, which includes:
• inspections at least monthly as part of the regular maintenance routine;
• applicable water treatment;
• regular microbiological monitoring; and
• cleaning regularly as necessary at intervals not exceeding six months.

Cooling water systems that have been shut down on a seasonal basis, or for more than 30 days, should be cleaned and suitable water treatment reinstated before    start-up.


Legionnaires’ disease

Legionnaires’ Disease is a type of pneumonia caused by breathing in legionella bacteria which live in water systems. Legionnaire’s disease is considered very serious and is responsible for numerous fatalities worldwide every year.
There have been 620 diagnosed cases in WA since 1999.

Given the serious nature of Legionnaires’ disease, and its potential to impact on a large number of people, notification of the disease is required under Western Australian law.

In particular, employers and self-employed people in control of workplaces are required to notify the WorkSafe Western Australia Commissioner or, in the case of mines, the District Inspector for the region in which the mine is situated, and the Department of Health, as soon as possible after a case occurs.

In 2010,  The Commission for Occupational Health published a Code of Practice for the Prevention and Control of Legionnaires’ disease based on the numerous safety regulations already in existence, giving guidance to employers on how to assess the risk and prevent legionnaires’ disease.

Section 1.6 of this code sets out a risk assessment strategy that involves identifying potential sources where legionella bacteria might exist in water systems in the workplace and then putting steps in place to remove or control the risk.

Relevant legislation for a legionella risk assessment

Occupational Safety and Health Act 1984:

legionella risk assessment perth

Health and safety is the responsibility of all people at a work site.

The employer’s general ‘duty of care’ obligations for safety and health under the OSH Act include:

  • providing a workplace and safe system of work so workers are not exposed to hazards, and risks of contracting Legionnaires’ disease
  • providing workers with information, instruction, training and supervision to enable them to work in a safe manner; and
  • consulting and cooperating with workers and safety and health representatives, where they exist, in matters related to safety and health at work.

Health (Air-handling and Water Systems) Regulations 1994:

The Health (Air-handling and Water Systems) Regulations 1994 have effect throughout Western Australia and apply to all buildings classified by the Building Code of Australia, with the exception of classes 1, 2 and 10 (ie domestic residences and non-habitable out-buildings).

These regulations apply to the operation and maintenance of air-handling and water systems and cooling towers whether installed before or after the gazettal date.

Manuals and records

Operating and maintenance manuals and maintenance records should be available for workplace equipment and systems. The operating and maintenance specifications and manuals should be provided by the manufacturer, designer, supplier or importer.

Where applicable, manuals and records should include:

  • a risk assessment and associated system specific management
  • physical details, including drawings of the equipment and systems, including associated pipework
    legionella risk assessment
  • manufacturers’ recommendations on maintenance, including water treatment maintenance and
  • recommended cleaning methods and dismantling instructions
    operating and shutdown procedures
  • date, item of equipment or system and nature of service performed
    water treatment reports and records
  • microbiological reports and records
  • roles and responsibilities associated with system operation
  • a defect and corrective action log
  • evidence of awareness training for individuals responsible for management and maintenance of the
    system, and
  • the name of the person or company performing the service.

These manuals and records should be readily available for workers who may require the information.