Legionella and cooling towers

Legionella bacteria are found in natural water sources like lakes, rivers and hot springs, as well as in soil. They can also grow in cooling towers as these systems often maintain water temperatures between 28°C and 45°C, which allows the bacteria to multiply. At Monash, cooling towers are used in air conditioning, refrigeration and industrial systems to help regulate temperature.

Legionnaires’ disease

Legionnaires’ disease is a rare type of pneumonia caused by Legionella bacteria. It usually starts with flu-like symptoms such as fever, muscle aches, and a cough. You might also feel tired or short of breath.

You can get Legionnaires’ disease by breathing in tiny droplets of water (aerosols) that contain the bacteria. It’s not spread from person to person, and you can’t get it by drinking contaminated water.

The infection is diagnosed through lab tests, including a sputum culture. It can be treated with antibiotics, but severe cases may require hospital care.

Who’s at risk

The disease does not affect everyone who comes into contact with the bacteria. The groups most at risk are:

  • people over 50 years of age (predominantly males)
  • heavy smokers and drinkers
  • diabetics
  • people with chronic lung disease or impaired immune systems.

How Monash manages Legionella

Monash University complies with all Victorian Government regulations, guidelines and standards for cooling tower safety.

Maintenance and treatment

  • Cooling towers are regularly cleaned, disinfected and tested for total bacterial count (TBC) and Legionella.
  • Most towers are fitted with automatic dosing systems that continuously release a broad-spectrum biocide to kill bacteria.
  • Some campuses also use alternative biocides applied by accredited contractors.
  • All towers are cleaned quarterly and tested monthly by an independent NATA-accredited lab.

System design and safety features

  • New cooling towers are fitted with drift eliminators to reduce the spread of aerosols.
  • Towers operate at relatively low temperatures (25–34°C), which helps limit bacterial growth.
  • Legionella testing is carried out according to the Victorian Department of Health’s cooling tower management program.

Accessing a roof near a cooling tower

You must get a permit to access a roof near a cooling tower. Buildings & Property must arrange to check the status of the cooling tower testing before issuing the permit.

Cooling tower testing report

Standards and guidelines

Procedures and guidelines

Need help?

Contact the Health Safety & Wellbeing team at hsw@monash.edu.