Legionella and legionnaires' disease

Legionellosis is the collective term given to the pneumonia-like illness caused by legionella bacteria. This includes legionnaires’ disease, as well as the less serious conditions of Pontiac fever and Lochgoilhead fever.

The risk of the legionella bacteria being present in church buildings is usually low, but it may be found in some hot and cold-water systems, pools, humidifiers, air washers, emergency showers or indoor ornamental fountains etc.

Are there legionella risks?

Any water system that has the right environmental conditions could potentially be a source for legionella bacteria growth. There is a reasonably foreseeable legionella risk in your water system if:

  • Water is stored or re-circulated as part of your system;
  • The water temperature in all or some part of the system is between 20–45 °C;
  • There are sources of nutrients such as rust, sludge, scale and organic matters;
  • The conditions are likely to encourage bacteria to multiply; and
  • It is possible for water droplets to be produced and, if so, if they can be dispersed over a wide area, e.g. showers.

It is likely that employees, residents, visitors etc will be more susceptible to infection due to old age, illness, a weakened immune system.

As an employer, or a person in control of the premises, you are responsible for health and safety and need to take appropriate precautions to reduce the risks of exposure to legionella. You must understand how to:

  • Identify and assess sources of risk;
  • Manage any risks;
  • Prevent or control any risks;
  • Keep and maintain the correct records;

You should carry out a risk assessment to identify what risks, if any, are present and manage any identified risks.

Some precautions you can undertake:

  • Control water temperature to avoid conditions that favour the growth of legionella;
  • Ensure the release of water spray is properly controlled;
  • Ensure water can’t stagnate in the system. Keep pipe lengths short and remove redundant pipework;
  • Keep the water system and water within it clean;
  • Arranging for air conditioning units and humidifiers to be cleaned and serviced regularly;
  • De-scaling showerheads and running showers periodically.

For more information please visit: Health and Safety Executive, Legionnaires disease – what you must do.