Legionella bacteria can only proliferate and increase in number under certain conditions. In order to control as well as manage Legionella through a Legionella Prevention Plan, it is best to be aware of these conditions, as well as managing Legionella in water systems.

rsz shutterstock 201510938

The conditions Legionella bacteria prefer include:

• Water temperatures between 20 degrees celsius and 45 degrees celsius
• Stagnation or low water turnover
• High microbial concentration, including algae, amoebae, slime and other bacteria
• Presence of biofilm, scale, sediment, sludge, rust or other organic matter

Luckily it isn't all water sources that are considered high risk of containing worrying amounts of Legionella bacteria; however the ones that are include:
• Water systems that contain a cooling tower or evaporative condenser
• Hot and cold water systems
• Hot tubs, whirlpool baths and spa baths
• Waterlines to dental chairs
• High-pressure water cleaning machines
• Other water systems with the chance of exceeding temperatures of 20 degrees celsius

Putting together a Legionella Prevention Plan

Legionella prevention plans must include controlling the growth of the bacteria by managing Legionella in water systems, as well as protecting against the inhalation of infected water droplets and aerosols. Some safety measures include:

• Avoiding water temperatures between 20 degrees celsius and 45 degrees celsius
• Avoiding water becoming stagnant, which could encourage the growth of a biofilm
• Maintain cleanliness of the water system and the water in it
• Personnel maintaining the water system may have to use personal Legionella control equipment, such as respirators
• Ensure that the release of water spray is properly controlled
• Avoid materials that encourage the growth of Legionella
• Treat the water to either kill any existing Legionella bacteria, or limit their ability to grow.