Legionnaires’ risk post lockdown

Businesses should carry out a detailed review of all aspects of their water management systems before reopening following the coronavirus (COVID-19) outbreak.

The combination of the recent warm weather and dormant water systems can create the perfect environment for Legionella bacteria to grow which could pose a threat to the public according Public Health England (PHE).

Legionella is naturally present in water systems and causes Legionnaires’ disease – a severe form of pneumonia. Any water system, with the right environmental conditions, could be a source for legionella bacteria growth. There is a reasonable legionella risk if your client’s water system:

  • has a water temperature between 20–45°C
  • creates and/or spreads breathable droplets e.g. aerosol created by a cooling tower, or water outlets
  • stores and/or re-circulates water
  • is likely to contain a source of nutrients for the organism to grow, e.g. rust, sludge, scale, organic matter and biofilms

The most common sources of legionella are in man-made water systems. It was recently reported by the BBC (external link) that three schools in Wales weren't able to re-open as bacteria that can cause Legionnaires' disease was found in pipes (see our Appetite guide for Adult Education and Learning establishments)  PHE stated that any business with a water supply that has been or is currently shutdown would need to take action. It singled out some businesses - hair salons, hotels, dental practices or sports clubs -as being at particular risk.

Employers, the self-employed and people who manage premises, such as landlords, have a duty to protect employees and tenants by identifying and controlling the risks associated with legionella

If your client’s building has been closed or has had reduced occupancy during the coronavirus (COVID-19) outbreak, water system stagnation may have occurred due to lack of use, increasing the risk of Legionnaires’ disease.

Policyholders should review their risk assessment and manage the legionella risks when they:

In addition where your client’s water system is used regularly, the appropriate maintenance measures need to be in place to prevent legionella growth.


Sources: https://www.hse.gov.uk/legionnaires/workplace-risks.htm (external link), https://www.hse.gov.uk/coronavirus/legionella-risks-during-coronavirus-outbreak.htm (external link) and https://www.bbc.co.uk/news/uk-wales-53243131 (external link)