top of page

How often should you update your Legionella Risk Assessment?

The HSE’s ACoP l8, states that a risk assessment should be reviewed whenever there is a reason to suspect that the current assessment may be invalid.

An indication of when to review the assessment may occur when any of the following occur;

·        Changes to the water system of its use

·        Changes to the use of the building in which the water system is installed

·        The availability of new information about risks and control measures

·        The results of checks indicate that control measures are no longer effective.

·        Changes to personal

·        A case of legionnaires disease/legionella associated with the system.

What guidance is provided?

The Frequency and extent of routine monitoring will depend on the operating characteristics of the water and the level of risk associated. The health and safety executive’s (HSE) approved code of practice L8 regulations say that employers are required “to review the assessment regularly and specifically when there is reason to believe that the original assessment is no longer valid”.

As a duty Holder what are my responsibilities?

If you are a person in control of a premises or an employer, you are responsible for taking the correct precautionary actions to reduce the risk of exposure to Legionella.

To comply with legal compliances those responsible for the control of a premises should;

·        Identify and assess the sources of risk at the premises.

·        Prepare a written scheme for preventing or controlling the risk – if appropriate.

·        Implement, manage, and monitor precautions.

·        Keep records.

·        Appoint a competent person with sufficient authority and knowledge of the installation to help take the measures needed to comply with the law. – If there isn’t anyone to do so work with a company who can carry out these tasks on the companies’ behalf. 

The assessment of risk is not an isolated process, once a Legionella Risk assessment is carried out it should be a continuous process of review and as a building evolves and increases in use then the processes within that building should also evolve. Even if the risk is relatively low within those premises, then the processes should still be reviewed.

Absolute Water Compliance recommends that Legionella checks should be instigated by the duty holder at which point the level of risk is determined, and depending on the level determines how frequent a Legionella risk assessment should be carried out. For example, in care homes and hospitals the level of risk is considerably higher and therefore a risk assessment should be carried out more frequently. In most cases a risk assessment should be carried out at a minimum of every two years.


Why is a Legionella risk assessment important, and why is it important to identify the risks?

Legionella Risk assessments help to identify potential hazards caused by pathogenic organisms e.g Legionella. Such organisms can arise during the maintenance, supply, storage, delivery, and use of water.

A Legionella risk assessment is crucial for several reasons, primarily centred around health, compliance, and effective risk management. Here's a detailed look at why it's important:


  1. Preventing Health Risks: Legionella bacteria is responsible for Legionnaires’ disease, a severe form of pneumonia. The risk is especially significant in places where water can stagnate or isn't properly maintained, such as in cooling towers, hot water tanks, showers, and complex plumbing systems. An assessment helps identify the conditions that allow the bacteria to proliferate, such as water temperatures between 20-45°C (68-113°F) and stagnant water, thereby guiding measures to control or eliminate these risks.

  2. Legal Compliance: Many countries have regulations that require building owners and facility managers to conduct Legionella risk assessments to ensure public safety. These regulations are often enforced by health and safety legislation, and failure to comply can result in substantial fines, legal action, or both.

  3. Operational Continuity: An outbreak of Legionnaires’ disease can lead to facility closures, significant public relations issues, and financial losses. By conducting a thorough risk assessment and implementing a water management plan, facilities can reduce the likelihood of such disruptions.

  4. Community Safety: Buildings that serve large or vulnerable populations, such as hospitals, hotels, and long-term care facilities, have a heightened responsibility to prevent outbreaks. Legionella bacteria pose a high risk to the elderly, those with weakened immune systems. Identifying and mitigating these risks helps protect not just individual health but public health as well.

  5. Cost Efficiency: Addressing risks before they escalate into problems can be far more cost-effective than dealing with the aftermath of an outbreak. Regular assessments and maintenance can prevent expensive remediation efforts and potential legal and medical costs associated with an outbreak.

Why It's Important to Identify the Risks:

  1. Targeted Action: Knowing specific risk factors, such as areas of stagnant water or optimal bacterial growth temperatures, allows for targeted interventions. This might include adjusting water temperatures, flushing out rarely used water lines, or regular cleaning and disinfection.

  2. Resource Allocation: By identifying where the risks are highest, resources can be efficiently allocated to areas that need the most urgent attention, thereby optimising the use of time and money.

  3. Documentation and Tracking: A risk assessment provides a documented basis for decision-making and can be used to track the effectiveness of interventions over time. This documentation is also important for compliance purposes and can be critical in legal contexts.

  4. Customisation of Control Measures: Not all buildings are the same, and thus, risk factors vary widely. A well-conducted Legionella risk assessment will consider the specific characteristics of a building or water system, leading to customised control measures that are much more effective than one-size-fits-all solutions.

Overall, conducting a Legionella risk assessment is a fundamental aspect of responsible facility management, crucial for protecting health and fulfilling legal and ethical obligations.


Water hygiene and risk assessments are is a continuous process that requires frequent and continual reviews and updates and are the key to mitigating Legionella within water systems.

Read Absolute Water compliance’s guide to obtaining a Legionella Risk assessment here. 

The frequency of which Legionella risk assessments need to be carried out should be determined by the level of risk within the premises, a legionella risk assessment is the first step towards compliance with the Health and safety Executives Legionella approved code of practice and guidance document, ACOP L8.

Do you require a trusted company to review your current processes and risk Assessment? Get in contact with absolute water compliance today for a FREE no obligation consultation.


Leginella risk assessment companies UK








6 views0 comments


bottom of page