What is Legionella?
Legionnaires' disease is a potentially fatal form of pneumonia caused by the inhalation of small droplets of contaminated water containing Legionella. All man-made hot and cold water systems are likely to provide an environment where Legionella can grow. Where conditions are favourable (ie suitable growth temperature range; water droplets (aerosols) produced and dispersed; water stored and/or recirculated; some 'food' for the organism to grow such as rust, sludge, scale, biofilm etc) then the bacteria may multiply thus increasing the risk of exposure. It is a simple fact that the organism will colonise both large and small systems so both require risks to be managed effectively.
What does the landlord need to do?
As the person controlling premises you need to decide what water installations or systems on the premises may give rise to a risk of Legionella. You can carry out a risk assessment yourself if you are competent, or you can employ an external contractor who is.
A simple Legionella risk assessment may show that there are no real risks from legionella and no further action may be required. However, it is important to review the risk assessment regularly in case anything changes.