Employers, the self-employed and people in control of premises, such as landlords, have a duty to protect people by identifying and controlling risks associated with legionella.

If your building was closed or has reduced occupancy during the coronavirus (COVID-19) pandemic, water system stagnation can occur due to lack of use, increasing the risks of Legionnaires’ disease.

You should review your risk assessment and and manage the legionella risks when you:

• reinstate a water system or start using it again
• restart some types of air conditioning units

If the water system is still used regularly, maintain the appropriate measures to prevent legionella growth.

You can find out what Legionnaires’ disease is, where it comes from, how people get it and symptoms and treatment by reading the HSE guidance What is Legionnaires’ disease?.