Legionnaires’ disease is a potentially serious form of pneumonia caused by inhaling water droplets contaminated with Legionella bacteria. Though uncommon, the consequences can be severe, which is why employers, dutyholders, and anyone responsible for premises across the UK must treat legionella as a critical health and safety and compliance issue.
However, if you are responsible for the management of a building, you may not be entirely clear on whether a formal legionella risk assessment will be required.
Confusion about when and where such a risk assessment is necessary often stems from outdated advice, varying guidance for domestic rentals versus commercial properties, and the lack of a fixed “certificate” or annual mandatory test in most cases.
Misunderstanding your obligations with regard to Legionella risk assessment, though, can lead to various serious consequences. You could be fined, prosecuted under health and safety law, or receive enforcement notices from the UK Health and Safety Executive (HSE).
So, in this article, we will seek to clarify the requirements for Legionella risk assessment under current UK law. The primary reference on this subject is the HSE’s Approved Code of Practice (ACOP) and guidance document under the L8 series code, Legionnaires’ disease: The control of legionella bacteria in water systems.
What is a Legionella risk assessment, and why is it a legal requirement?
A legionella risk assessment is a systematic review aimed at identifying potential sources of legionella in water systems, evaluating the level of risk to people, and determining what practical measures are necessary to prevent or control exposure.
Hot and cold water systems need to be accounted for in a legionella risk assessment, as well as any other systems where water can aerosolise (in other words, potentially become airborne in droplets that people can breathe in). So, this also encompasses such areas of a property with any cooling towers, spa pools, showers, and/or humidifiers.
A legionella risk assessment is a legal requirement under several key pieces of legislation in the UK, including:
- Sections 2, 3, and 4 of the Health and Safety at Work etc Act 1974
- The Management of Health and Safety at Work Regulations 1999
- The Control of Substances Hazardous to Health Regulations 2002 (COSHH), which specifically covers biological elements like Legionella
The aforementioned ACOP L8 document, available as a free PDF on the HSE website, provides practical guidance on compliance with these laws.
The HSE guidance emphasises a risk-based approach under the principle of “reasonably practicable”. Responsible persons are expected to take sensible and proportionate action to control risks, balancing cost, time, and trouble against the specific level of risk.
Even if you believe the legionella risk is low in a given building for which you are responsible – for example, because it is a small domestic property with straightforward plumbing – a legionella risk assessment is still required.
This is because there can be scope for Legionella to proliferate in stagnant water, in temperatures between 20°C and 45°C, or in poorly maintained systems. Arranging for a legionella risk assessment to be performed can help confirm the low risk, in addition to documenting that you have carried out due diligence.
Who needs a legionella risk assessment, and in what types of buildings?
If you have a duty under health and safety law, and would therefore be considered a “dutyholder”, you are legally obliged to assess and control legionella risks at a property for which you are responsible.
Examples of such individuals include:
- Employers, in the case of workplaces
- Landlords, including those renting out houses, flats, rooms, or Houses in Multiple Occupation (HMOs)
- Managing agents
- “Responsible persons”, often appointed in larger organisations
The need for a legionella risk assessment applies to these types of buildings:
- Commercial buildings such as offices, shops, hotels, and factories
- Workplaces of any size
- Residential rental properties (domestic tenancies)
Environments that pose a particularly high risk from a legionella perspective include hospitals, care homes, hotels, leisure centres, and any other buildings with vulnerable occupants, such as the elderly, immunocompromised, or those with respiratory conditions. In such premises, systems like showers, cooling towers, or spa pools can heighten aerosol exposure.
Even in relatively simple setups – for example, a small office or rental house with standard hot and cold water systems – it may still be necessary to arrange a formal assessment, even though this can often be straightforward.
In multi-occupied and managed buildings, responsibilities may be shared; for example, the landlord may be responsible for common parts of a given property, and tenants for private areas. So, clear agreements are essential for setting out who is responsible for which areas.
When does a Legionella risk assessment need to be carried out or reviewed?
An initial Legionella risk assessment will be required at your premises before people are exposed to the water systems. This essentially means the review will need to be carried out when you take control of a property that has such water systems.
Triggers for a review or a new legionella risk assessment include:
- Changes to water systems, such as new installations, modifications, or refurbishments
- Changes in a building’s occupancy or how it is used (for example, higher numbers of vulnerable people using the property)
- Periods of low use, extended shutdowns, or recommissioning, given the risk of stagnation bringing about legionella bacteria in the building’s water systems
- Any reason to suspect the previous assessment has ceased to be valid (such as if new evidence of issues has emerged).
Legionella risk assessments do not come with a fixed expiry date, such as “every two years”. Instead, the ACOP L8 publication states that assessments must be reviewed regularly, or whenever circumstances change.
Low-risk domestic rentals might not be subject to reviews as frequently as environments associated with a higher legionella risk. However, even for properties in the former category, experts recommend checking every two years as a practical benchmark, or sooner than this if changes occur.
In higher-risk or more complex systems, reviews being carried out more frequently greatly helps ensure the legionella risk assessment’s ongoing validity.
Can you manage Legionella risk without a professional assessment?
In some cases, the answer to this question may be “yes”. If you are a landlord for low-risk domestic rentals, it may be acceptable to carry out your own simple in-house assessment.
Indeed, the HSE has noted that domestic properties don’t usually require in-depth legionella assessments or routine testing.
However, there is a critical caveat to add on legionella risk assessments in lower-risk settings: the person conducting the review must be competent. This means they are required to be suitably informed, instructed, trained, and experienced.
If the given person performing the internal legionella risk assessment lacks the competence to carry out this review, they could be susceptible to certain classic mistakes. Such oversights can include leaving records incomplete, missing hidden risks such as dead legs, and/or relying too much on generic templates that don’t reflect the given property’s specific system.
“Paper compliance”, by which we mean ticking certain boxes without establishing a proper understanding of the risks, often fails during audits or incidents. So, it is in the interests of dutyholders and responsible persons to ensure competence to do the risk assessment.
Why is professional support critical for effective Legionella compliance management?
There is a significant distinction to be made between “merely” completing a single legionella risk assessment and effectively managing ongoing risk at a particular premises.
This is where the right professional help can have a major impact. Although assistance from a third party isn’t always essential in every case, suitably qualified and well-informed professionals can greatly help dutyholders to interpret legionella-related legislation and guidance correctly.
When you reach out to reputable experts, such as our team at Assets & Compliance Managed Services (ACMS), they can also help gather independent evidence of compliance for regulators and insurers. Moreover, they can provide support in relation to control schemes, monitoring, and corrective actions.
Joining forces with the right external professionals, then, can greatly contribute to your efforts as a dutyholder to reduce long-term legionella risk at any property you are responsible for. This, in turn, will help ensure you aren’t always merely “reacting” to compliance problems.
Conclusion: How can you be confident you are meeting your Legionella obligations?
In summary, if you are a dutyholder, landlord, or responsible person with control over premises that contain water systems, you will need a legionella risk assessment for them. This process will be vital for identifying, evaluating, and controlling risks with regard to Legionella.
Timely initial assessments, regular reviews triggered by changes, and competent input will all be crucial in the management of Legionella risk. You certainly shouldn’t wait for issues to arise; instead, you should adopt a proactive, risk-based mindset.
Fortunately, Legionella compliance at your premises can be manageable with the right structure and support. Enquire to the ACMS team today, and we will be pleased to outline further information about the software, services, or compliance solutions we can provide.
