Legionella bacteria in water systems can cause serious illnesses. This guide outlines employers, landlords, and others’ responsibilities and how to carry out a Legionella risk assessment.
Water systems in offices, factories and other premises could potentially be a source of legionellosis, the collective term for illnesses caused by Legionella bacteria (Legionella pneumophila). The illnesses include Pontiac fever and Lochgoilhead fever but the most serious is Legionnaires’ disease, a pneumonia-like illness which can be fatal.
Read our guide to what is Legionella and how dangerous it is.
All premises where water is stored or distributed are at risk of exposure to Legionella, so employers or those in charge of premises such as landlords are required to carry out a risk assessment and put adequate controls in place.
Help control exposure to Legionella with our IOSH Approved Legionella Awareness Training course, including the importance of Legionella risk assessments and duty holder responsibilities.
What is a Legionella risk assessment, and why is it necessary?
Every organisation where man-made water systems are used must carry out a Legionella risk assessment to identify potential dangers to employees, customers and others.
Legionellosis is rare, with just 295 cases reported January to October 2020 in England and Wales by Public Health England, with most cases down to community transmission. However, because the effects can be serious, duty holders and others must understand Legionella and take suitable precautions.
People who contract Legionnaires’ disease from exposure to contaminated water droplets suffer flu-like symptoms that can progress to pneumonia. In severe cases, it can be fatal. Those at high risk of serious illness include people aged over 45, heavy smokers and drinkers, sufferers of chronic respiratory or kidney disease and anyone with an impaired immune system.
A Legionella risk assessment is required to identify and assess the sources of risks from the bacteria. The risks must be managed with the appointment of a competent person. The risks must then be prevented or controlled with suitable measures through a ‘Written Control Scheme’ development and implemented.
Who needs to carry out a Legionella risk assessment?
Under the Control of Substances Hazardous to Health Regulations 2002 (COSHH), employers, managers, landlords, and duty holders are responsible for assessing, controlling, and maintaining the risk of Legionella exposure from water systems.
Legionella bacteria are found in rivers, lakes and ponds yet pose few risks in these natural environments. However, when present in man-made water systems, the bacteria can multiply and be harmful when airborne in water droplets. Air conditioning systems, cooling towers, humidifiers, hot and cold water systems, showers, spas and hot tubs are common man-made environments where Legionella bacteria can grow.
Due to these risks, employers must carry out a risk assessment. Rented domestic properties have a low risk of Legionella, but landlords must still assess the risks.
Who can carry out a risk assessment?
The HSE’s Legionnaires’ Disease – The Control of Legionella Bacteria in Water Systems Approved Code of Practice L8 states that “the duty holder must ensure that the person who carries out the risk assessment and provides advice on control of exposure must be competent to do so”.
An employer, landlord or someone else in control of the premises may have the necessary knowledge to complete a Legionella risk assessment, particularly for simple water systems such as in domestic properties. However, for more complex systems such as cooling towers and commercial water supplies, a specialist with expert knowledge from within the organisation or an external consultancy may be required to take on the role.
Using a specialist service such as Praxis42’s Legionella water risk assessment will identify a need for a more in-depth risk assessment.
A qualified and experienced adviser will visit the premises to identify factors or system designs that require a more detailed assessment of the premises’ water system.
Landlords of residential properties have a duty to protect tenants’ safety by assessing the risks of exposure to Legionella, but a detailed assessment may not be required.
How to carry out a Legionella risk assessment
The person responsible for managing risks in the organisation (The Duty Holder) needs to understand the water system and the associated equipment such as showers and pumps. You may need to get help from an outside source, such as using a professional Legionella water risk assessment service.
A Legionella risk assessment should follow this process:
Identify the sources of risk and who is at risk
The assessment should identify whether conditions in the water systems are likely to lead to bacteria multiplying, which creates a risk from exposure to Legionella. It should look at areas including:
- Water systems maintenance and inspection arrangements.
- Whether the temperature in all or parts of the system is between 20-45 degrees Celsius which is ideal for the harmful proliferation of Legionella bacteria.
- Whether there are sources of nutrients such as rust, sludge, scale and organic matter.
- If it is possible for water droplets to be produced and spread over a wide area.
The risk assessment should identify who is likely to be affected by contaminated water droplets and how. You should pay particular attention to employees, visitors, contractors, residents and others who are in high-risk groups such as older people, heavy smokers and those with an impaired immune system.
The risk assessment should assess management responsibilities including the name of the Duty Holder, the person appointed as the responsible, competent person, as well as the training and competence level of key employees and others who need to be aware of the risks from Legionella.
The Health and Safety Executive says those appointed to implement control methods should “be suitably informed, instructed and trained” so Legionella awareness training should be put in place to prevent exposure and the outbreak of illnesses.
The risk assessment should also assess the organisation’s monitoring and maintenance procedures and the results of previous checks. It should have a Legionella policy and written scheme of controls based on the risk assessment.
Managing, prevent and control the risks
The Duty Holder must appoint a responsible person to manage the risk identified in the risk assessment. They must be competent, which means they have the necessary skills, knowledge, training and experience to carry out the role. The person can be the duty holder, one or more employees or someone from outside the organisation.
The assessment should first consider whether the risk of Legionella is being prevented by the design of the water systems. If the assessment identifies risks that cannot be prevented by design, you must develop a written scheme of controls that outlines the methods you will implement and who is responsible for managing their implementation. It should also record what checks will be carried out to ensure that the controls are being implemented and working and the frequency of the checks, such as flushing or running unused systems weekly.
Systems should be regularly inspected and maintained with water temperatures monitored where the written scheme defines the requirement. Systems and water should be kept clean, and water may need to be treated with a biocide to control or limit the growth of Legionella and other micro-organisms. In addition, water should not be allowed to stagnate by keeping pipe lengths short or removing unnecessary pipework.
Keep records
Records should include the findings of the assessment, the steps taken to control or prevent the risks and the results and dates of maintenance, inspections and tests.
The records should be kept for at least two years. The results of inspections and tests should be retained for at least five years.
While they are not required to do so, it is recommended that organisations with under five employees and landlords also keep a record.
Review the assessment
The assessment records should be kept up to date and reviewed regularly or when any changes are made to the organisation’s water systems, or there have been concerns from the findings of compliance inspections, audits, or there has been an incident relating to the water system.
Get expert, specialist advice with Praxis42’s Legionella Water Risk Assessment service. A competent person can visit your premises to determine if a full Legionella risk assessment and prevention plan needs to be established.
