Legionella Testing for Landlords

Landlords are responsible for the health and safety of their tenants, including the risk of legionella bacteria in their water systems. In this blog, Frontline Safety will tell you everything you need to know about the legionella testing responsibilities for landlords.

What is Legionella?

Legionella is a bacteria that can be found in water stored at temperatures between 20 and 45 Celsius. This bacterium is harmful to humans and can lead to legionnaires disease. Read our dedicated legionella application note to find out more about the disease.

Legionella Risk in Residential Properties

As legionella likes to grow in water stored at 20-45 Celcius, there are many areas of risk in residential properties. Properties can be split into two types – those that use mains water and others that use a water storage tank. Water storage tanks pose a much higher risk than the main water supply. Properties with cold water storage tanks are at particular risk when water sits and builds up biofilm - where legionella grows. This can spread to showers and tanks and infect humans through contact with the water. Therefore, water must be stored below 20 Celsius to control legionella growth. Hot water tanks are slightly less risky due to the higher temperature making it harder for bacteria to live.

Places of legionella risk in domestic properties include –

Water tanks and systems, particularly open water tanks.
Water droplets and aerosols from showerheads and whirlpool baths.
Environments between 20 and 45 degrees.
Water particles in the air.
Rust, scale and sludge that can feed bacteria.
Properties that lay vacant over long periods of time.
Older buildings have a higher risk.

The most significant legionella risk found to habitants of properties is the shower, especially when it has gone unused for periods, i.e. between vacancies. As mentioned previously, bacteria grow in the biofilm and biofilm forms when the shower is not in use. As a shower head spits water out aerosol-like, this is the perfect way to spread the bacteria. However, legionella can live anywhere in the shower water system, from the head to the tank.

Landlords Responsibility

The Health and Safety Executive states –

"Section 3(2) of the Health and Safety at Work Act 1974 (HSWA) makes provision for relevant health and safety legislation to apply to landlords to ensure a duty of care is shown to their tenants concerning their health and safety. The general duties required under section 3(2) that "It shall be the duty of every self-employed person to conduct his undertaking in such a way as to ensure, so far as is reasonably practicable, that he and other persons (not being his employees) who may be affected thereby are not thereby exposed to risks to their health or safety.". Landlords, under Section 53 of HSWA are regarded as being self-employed and tenants fall into the class of "other persons (not being his employees)". If you rent out a property, you have legal responsibilities to ensure you conduct your undertaking in such a way that your tenant(s) are not exposed to health and safety risks."

Landlords are legally responsible for assessing and controlling the risk of human exposure to legionella. Therefore, landlords must carry out a legionella risk assessment to ensure they are exercising their duty of care to protect the health and safety of their tenants.

A Legionella risk assessment includes –

Identifying the hazard and the level of risk
Identify who is at risk
Carry out testing on the water system
Take action and use control measures to minimise the risk
Record the outcome of the assessment
Review assessment

It is recommended that legionella risk assessments should be carried out every two years or before a new tenant enters the property. Landlords can also test for legionella by themselves with no prior training or experience – as long as they feel confident enough to do so, i.e know the essential properties of a water system. Frontline Safety recommends for landlords to conduct a risk assessment using the ETI Legionnaires' Kit. This testing kit comes with everything you will need to test for legionella and includes a free traceable calibration certificate. Read our dedicated blog to find out what is in the kit – How do I detect Legionella using ETI's Legionnaires Thermometer Kit?

How Can Legionella be Prevented?

The landlord can take measures that will prevent or minimise the likelihood of legionella bacteria growing in residential properties. Simply keeping the stored water temperature at the correct levels is the most effective way to minimise the risk. Other preventative measures include flushing a system before and after different tenancies, ensuring systems remain secure and free from debris and removing redundant pipework.

When rental properties are not in use, landlords should try and prevent the water from stagnating in the water system and should try and use the system at least once a week to maintain water flow. Suitable arrangements and regimes should be put in place to arrange this. Tenants should also do their part to prevent legionella from forming by not altering the temperature settings of the calorifier and regularly cleaning and disinfecting shower heads.