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What is legionella?

There are many different types of Legionella bacteria found in the environment.  Legionella pneumophila is the most common type found in water, and causes Legionnaires’ disease.

Legionella bacteria must be inhaled to cause illness. However, most people who are exposed to aerosols containing Legionella do not become ill. Legionella can infect the lungs, causing a disease known as legionellosis.

Cooling and Warm Water Systems

If not properly operated and maintained, cooling water systems and warm water systems are ideal breeding grounds for Legionella bacteria, which can infect people working and living nearby.

To reduce the risk of infection, your maintenance staff and contracters must adhere to South Australian Public Health (Legionella) Regulations 2013 and the Guidelines for the Control of Legionella in Manufactured Water Systems in South Australia.

What is a cooling water system?

A cooling water system, which includes a cooling tower or evaporative condenser, is a heat-exchange system. It consists of a heat generating plant, a heat rejection plant, interconnecting water recirculating pipe work and associated pumps, valves and controls. 

What is a warm water system?

Warm water systems are designed to heat and deliver water at a temperature of less than 60°C and are often found in places where they are used to minimise the risk of scalding, such as nursing homes, childcare centres and hospitals. As a result, the water temperature is suitable for Legionella and other bacteria to grow.

Inspections and Regulations of Cooling and Warm Water Systems

The South Australian Public Health (Legionella) Regulations 2013 details what you need to do to reduce the risk of infection in Manufactured Water Systems.

They should be read in conjunction with The Guidelines for the Control of Legionella in Manufactured Water Systems in South Australia.

Requirements include:

  • registering all high-risk manufactured water systems with EHA, and renewing this registration each year
  • fitting specific equipment, such as automatic biocide dosing devices and drift eliminators on cooling towers
  • periodic preventative maintenance, such as inspections and cleaning
  • responding to any Legionella detection

Under the Regulations, EHA inspects all registered high-risk manufactured water systems, and may inspect systems at any time in relation to disease investigations, reports of non-compliance, Legionella detection or complaints.

For further information please visit the SA Health website

Useful links

Controlling Legionella in the home

There are a few things around your home that may carry a risk of Legionella pneumophila infection, including

  • hot water systems
  • hot water taps
  • spa pools
  • spa baths
  • therapeutic nebulisers and humidifiers
  • fountains
  • evaporative air conditioners
  • portable evaporative cooling units

Soil and potting mix

Legionella longbeachae is common in the soil and potting mix and generally causes lung infections.

Reduce your exposure to potting mix dust by:

  • wetting down the potting mix to reduce dust
  • wearing gloves and a class P2 dust mask when using potting mix
  • washing your hands after handling potting mix or soil, and before eating, drinking or smoking
  • following the manufacturers' warnings present on potting mix labels

The SA Health website has more information on how to control Legionella in your home.

For more information, call EHA on 8132 3600 or email

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