Legionella is a risk that no business responsible for a building’s water systems should overlook. Although Legionella bacteria can occur naturally in water, certain conditions within man-made water systems can allow the bacteria to multiply and create a potential risk to people’s health.
For employers, landlords and those responsible for commercial or public premises, understanding and managing this risk is an important part of maintaining a safe environment and meeting health and safety responsibilities.
One of the most important steps in managing Legionella is carrying out a suitable and sufficient Legionella risk assessment.
What is a Legionella risk assessment?
A Legionella risk assessment is a structured assessment of a building’s water systems to identify where Legionella bacteria could grow and how people could potentially be exposed.
The assessment considers the water system as a whole rather than simply looking at individual outlets. This can include water storage tanks, hot and cold water systems, calorifiers, pipework, showers and other equipment that may create or distribute water droplets.
The Health and Safety Executive (HSE) explains that a risk assessment should identify potential sources of risk and help determine the measures necessary to prevent or adequately control exposure to Legionella.
A professional assessment can therefore provide a clear picture of the condition of a water system and highlight areas where improvements may be required.
Why are Legionella risk assessments important?
Legionella bacteria can multiply when suitable environmental conditions exist within a water system. Factors such as water temperature, stagnant water, poor circulation, scale, sludge, biofilm and redundant sections of pipework can contribute to the risk.
The HSE identifies water systems maintained within certain temperature ranges, systems that store or recirculate water, and systems that generate breathable droplets as circumstances where a foreseeable Legionella risk may exist.
If contaminated water droplets become airborne and are inhaled, they can potentially cause Legionnaires’ disease, a serious form of pneumonia.
A risk assessment helps those responsible for a building understand where these risks may exist and what measures can be introduced to reduce them.
Who needs a Legionella risk assessment?
The responsibility for managing Legionella risks can apply to a wide range of organisations and premises.
This can include:
- Offices and commercial buildings
- Schools, colleges and universities
- Care homes
- Healthcare facilities
- Hotels and other accommodation
- Leisure facilities
- Industrial and manufacturing premises
- Retail premises
- Housing associations
- Local authority buildings
- Landlords and property managers
The HSE states that employers and people in control of premises, including landlords, have responsibilities for identifying and managing Legionella risks.
The level of risk will vary depending on the individual building and its water systems. Not every premises will require complex control measures, but a suitable assessment is important for establishing what is appropriate for that particular property.
What does a Legionella risk assessment look at?
A competent assessor will consider the design, condition and use of the water systems within a building.
Depending on the property, an assessment may include inspection of:
Hot and cold water systems
Hot and cold water systems are among the most common areas considered during a Legionella assessment. The assessor will consider how water is stored, distributed and used throughout the building.
Water storage tanks
Stored water can present additional considerations, particularly where tanks are poorly maintained, incorrectly sized or contain areas where water can stagnate.
Calorifiers and water heaters
The assessor will examine relevant hot water equipment and consider how temperature is controlled throughout the system.
Pipework
The design and condition of pipework can have a significant impact on water hygiene. Redundant pipework, dead legs and areas of poor circulation can create conditions that need to be addressed.
Showers and spray outlets
Outlets that produce aerosols can be particularly important because contaminated droplets can potentially be inhaled.
Temperature control
Temperature management is an important part of Legionella control. The assessment will consider whether the system is being operated and managed appropriately.
Existing control measures
An assessment should also consider the procedures and monitoring already in place. This can include temperature monitoring, flushing regimes, maintenance records and other water hygiene controls.
The HSE’s guidance emphasises the importance of considering the individual characteristics of the site and assessing the water system as a whole.
What happens after a Legionella risk assessment?
A risk assessment should not simply identify problems without providing a practical way forward.
Following an assessment, the findings should be documented clearly, including any areas of concern and recommendations for managing or reducing identified risks.
Depending on the findings, recommendations could include changes to water system management, improvements to temperature control, removal of redundant pipework, additional monitoring or other remedial measures.
The purpose is not necessarily to eliminate every instance of Legionella bacteria. Instead, the objective is to identify foreseeable risks and put suitable controls in place to prevent or adequately control exposure.
How often should a Legionella risk assessment be reviewed?
A Legionella risk assessment should not be treated as a document that is completed once and then forgotten.
Buildings and water systems can change over time. For example, alterations to plumbing, changes in building use, periods of vacancy or changes to equipment could affect the level of risk.
The HSE advises that assessments should be reviewed when there is reason to believe that the original assessment may no longer be valid, as well as when circumstances change.
Regular review helps ensure that the assessment continues to reflect the actual condition and use of the building.
Do I need Legionella testing as well as a risk assessment?
This is a common question, and the answer depends on the individual circumstances and findings of the assessment.
A Legionella risk assessment identifies and evaluates potential risks within a water system. Legionella sampling or testing, meanwhile, involves taking water samples and analysing them for the presence of Legionella bacteria.
Testing can be an important part of a wider water hygiene management programme where it is appropriate based on the risk profile of the premises.
However, simply testing water does not replace the need to understand how the water system is designed, operated and maintained.
The risk assessment should form part of a wider approach to managing Legionella, alongside appropriate control measures, monitoring and record keeping.
Why use a professional Legionella risk assessor?
A Legionella risk assessment needs to be suitable for the individual premises and water system.
Where an organisation does not have the necessary knowledge, experience and expertise internally, the HSE advises that competent specialist help may be required.
Using a competent professional can provide an independent assessment of the water system and help ensure that potential issues are properly identified.
At Absolute Water Compliance, assessments are designed to provide practical recommendations that businesses and property managers can understand and act upon. Assessments can cover areas including hot and cold water systems, storage tanks, water heaters, pipework, temperature controls, dead legs, showers and existing management procedures.
Legionella risk assessments in Sheffield
For businesses, landlords and organisations in Sheffield, having access to a local specialist can make arranging an assessment straightforward.
Absolute Water Compliance provides Legionella risk assessments across Sheffield and the surrounding areas, covering commercial premises, schools, healthcare facilities, hotels, industrial sites and other properties. Their assessments are designed to identify potential risks and provide clear recommendations for maintaining safe and compliant water systems.
If you are responsible for a property in Sheffield and need to arrange an assessment, you can find out more about the service here:
Legionella Risk Assessment Sheffield – Absolute Water Compliance
Protecting your building and the people who use it
Legionella management is an ongoing responsibility rather than a one-off exercise. Understanding the risks associated with your water systems, implementing appropriate control measures and regularly reviewing your arrangements can help reduce the potential for exposure.
A professional Legionella risk assessment provides an important starting point by giving you a clearer understanding of your water system and identifying areas that may require attention.
Whether you manage an office, school, care home, hotel, industrial premises or rental property, taking a proactive approach to water hygiene can help protect building occupants while supporting your wider health and safety responsibilities.
If you are unsure whether your current Legionella risk assessment is suitable, has become outdated or you have never had one completed, speaking to a competent Legionella specialist is a sensible first step.
