What is Legionella, anyway?

Legionella is the bacterium that causes Legionnaire’s disease, a severe form of pneumonia. Normally, those who catch the disease do so by inhaling the bacteria from water or soil, as opposed to person to person contact. Those with weak immune systems, such as the elderly or smokers, tend to be more susceptible to the disease.

Landlords, employers, hotel operators and hospital administrators are legally required to assess the risk of legionella developing their space. There are three main risks factors that need to be assessed and mitigated:

1.  Redundant Piping or Dead Legs

Stagnant water is a breeding ground for Legionella. Improperly removed or rarely used water outlets often lead to this. The way to mitigate the risk is to survey the water system and manage any redundant pipework.

2.  Infected Cold Water Storage Tanks

Another condition for legionella to rapidly multiply is the lack of residual disinfectants like chlorine in cold water storage tanks. Routine cleaning of these should take place.

3.  Lukewarm Water Temperature

The temperature of hot and cold tap water should remain 50 degrees Celsius or above and 20 degrees Celsius or below, respectively, while the water temperature inside the boiler should be kept at or above 60 degrees celsius. Legionella exponentially grows in warm water temperatures, ranging from 25-42 degrees Celsius.

A Legionella Risk Assessments evaluates these factors through a systematic evaluation of the property and its installations. If you’re a landlord, the results of the report must be shared with the tenant, as they often include recommendations on optimal care for the property to mitigate risk (for example, that the showerhead should be disinfected regularly).  

Not only is a Legionella Risk Assessment a legal requirement – it’s the right thing to do as responsible landlords to provide as safe a space as possible for our tenants.