Is a Legionella Risk Assessment Mandatory?

A Legionella risk assessment is mandatory under UK health and safety law. The Control of Substances Hazardous to Health (COSHH) Regulations 2002 require employers, landlords, and those in control of premises to assess and control the risk of exposure to Legionella bacteria. Additionally, the Health and Safety Executive (HSE) also states that a Legionella risk assessment is a legal requirement for employers, landlords, and those in control of premises.
It’s crucial that you understand the legalities surrounding Legionella risk assessments; not doing so could result in you causing serious illness. This guide covers everything you need to know about Legionella risk assessments and what you need to do.
The Importance of Legionella Risk Assessments for All Water Systems
Legionella bacteria are commonly found in natural water sources, such as rivers and lakes, but can also be present in man-made water systems, including hot and cold water systems. The risk of exposure to Legionella bacteria from hot and cold water systems is a significant concern, as it can lead to Legionnaires’ disease, a severe form of pneumonia that can be fatal.
Legionella bacteria can occur in water systems due to factors such as water temperature, stagnation, and the presence of nutrients for bacterial growth. This can be further exacerbated by factors such as poor maintenance, infrequent use of taps, and inadequate cleaning.
It is crucial to assess and control the risk of exposure to Legionella bacteria in these systems through regular Legionella risk assessments.
Learn how Legionella grows and spreads
What Is a Legionella Risk Assessment?

A comprehensive Legionella risk assessment involves identifying potential sources of Legionella bacteria in a water system, assessing the level of risk, and implementing appropriate control measures. The specific requirements of a risk assessment will vary depending on the type of water system and the building it is in. For instance, an industrial facility will have different needs than a residential block.
In general, a Legionella risk assessment includes:
- An initial inspection
- Identification of risk areas through sampling and testing
- Assessment of existing control measures
- Review of monitoring and maintenance programmes
- Recommendations for prevention and control
Legal Requirements Surrounding Legionella Risk Assessments
Under UK law, employers, landlords, and those in control of premises are required to assess and control the risk of exposure to Legionella bacteria in their water systems. This legal requirement is established under the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health (COSHH) Regulations 2002.
The Approved Code of Practice (ACOP) L8 and HSG274 Legionnaire’s disease: Technical guidance provides detailed guidance on how to comply with these legal requirements. The documents set out a framework for controlling the risk of exposure to Legionella bacteria, including the requirement for a Legionella risk assessment.
Is a Legionella Risk Assessment Mandatory for Landlords?
Landlords are also legally required to conduct a Legionella risk assessment. The Health and Safety Executive (HSE) states that landlords have a legal duty to ensure the health and safety of their tenants, and this includes assessing and controlling the risk of exposure to Legionella bacteria in their properties.
Failure to do so could result in prosecution.
Is a Legionella Risk Assessment Mandatory in Scotland?
Yes, a Legionella risk assessment is mandatory in Scotland under the same UK legislation as in the rest of the UK: the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health (COSHH) Regulations 2002.
Additionally, the Scottish government has its own guidance document, “Scottish Health Technical Memorandum 04-01: The control of Legionella in healthcare premises”, which provides specific guidance for healthcare facilities in Scotland.
Who Is Responsible for Conducting Legionella Risk Assessments?
In the UK, the responsibility for conducting Legionella risk assessments lies with:
- Employers
- Landlords
- Facilities managers
How Often Should Legionella Risk Assessments Be Conducted?
The frequency of conducting Legionella risk assessments depends on the type and size of the water system and the level of risk associated with it. The HSE recommends that risk assessments should be reviewed regularly and, in some cases, conducted every two years.
More frequent assessments may be necessary if there are significant changes to the water system, such as changes to the use of the building or the water supply, changes to the pipework, or if there have been any incidents of Legionnaires’ disease associated with the water system.
Regular monitoring and maintenance of water systems are also necessary to ensure the continued effectiveness of any control measures implemented as a result of the risk assessment.
It is important to note that this is just a guideline, and the frequency of assessments may vary depending on individual circumstances. It is the responsibility of the person in control of the premises to determine how often assessments should be conducted.
Accredited Legionella Risk Assessments for Your Peace of Mind
Protect your business properties and keep your water systems safe from Legionella exposure by scheduling a Legionella risk assessment with Guardian Hygiene Services. Our experienced team of accredited technicians will assess and control the risk of Legionella bacteria, ensuring you meet legal requirements and prevent potential health hazards.
We are a trusted provider of water hygiene and Legionella control services with industry accreditations from the Legionella Control Association and CHAS, Constructionline, SafeContractor and the BSI. Our tailored solutions suit your specific needs and ensure compliance with all relevant regulations.
Don’t wait until it’s too late – contact us today to schedule your Legionella risk assessment.