If you are an employer, or someone in control of premises, including landlords, you must understand the health risks associated with Legionella.
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.
The law is clear that if you are a landlord and rent out your property (or even a room within your own home) then you have legal responsibilities to ensure the health and safety of your tenant by keeping the property safe and free from health hazards.
What you must do
The practical and proportionate application of health and safety law to landlords of domestic rental properties is that whilst there is a duty to assess the risk from exposure to Legionella to ensure the safety of their tenants, this does not require an in-depth, detailed assessment. The risks from hot and cold water systems in most residential settings are generally considered to be low owing to regular water usage and turnover. A typical ‘low risk’ example may be found in a small building (eg housing unit) with small domestic-type water systems, where daily water usage is inevitable and sufficient to turn over the entire system; where cold water is directly from a wholesome mains supply (no stored water tanks); where hot water is fed from instantaneous heaters or low volume water heaters (supplying outlets at 50 °C); and where the only outlets are toilets and wash hand basins.
What your tenant needs to know
Tenants should be advised of any control measures put in place that should be maintained eg not to adjust the temperature setting of the calorifier, to regularly clean showerheads and tenants should inform the landlord if the hot water is not heating properly or there are any other problems with the system so that appropriate action can be taken.