Legionella management is an essential part of building safety, but it is often overlooked until there is a concern.
For commercial properties, the risk is not limited to large or complex sites. Any building with water systems has the potential to create conditions where legionella bacteria can grow if systems are not properly managed.
For facilities managers, property managers, landlords and dutyholders, the key is prevention. A proactive approach helps protect building users, support compliance and reduce the risk of serious health and safety issues.
Legionella is a type of bacteria that can grow in water systems under certain conditions.
If water droplets containing legionella bacteria are inhaled, they can cause Legionnaires’ disease, a potentially serious form of pneumonia. The risk is higher in water systems where water is stored, circulated, warmed or left stagnant.
Legionella can be found in both natural and man-made water systems, but in commercial buildings the main concern is how water systems are designed, used and maintained.
Commercial properties often have more complex water systems than domestic homes. They may include stored hot and cold water, rarely used outlets, showers, tanks, pipework, calorifiers, cooling systems or other equipment that can create water droplets.
Legionella risk can increase when:
This is why legionella control needs to be managed consistently, not treated as a one-off task.
In the UK, those responsible for premises have legal duties to assess and control the risk of legionella.
This may include:
The dutyholder must ensure that legionella risks are identified, managed and kept under review. In practice, this means having suitable procedures, clear responsibilities and evidence that control measures are being carried out.
Legionella management is not just about carrying out a one-off risk assessment. It is an ongoing process that should be built into wider facilities management and compliance planning.
A strong approach will usually include:
A legionella risk assessment identifies potential sources of risk within the water system. It considers how the system is designed, how water is stored and distributed, who may be exposed, and whether current controls are suitable.
This is the foundation of effective legionella management.
Where risks are identified, a written scheme should set out how those risks will be managed. This may include temperature control, flushing regimes, inspection schedules, monitoring requirements and maintenance actions.
The scheme should be practical, clear and relevant to the site.
Water systems need to be checked regularly to ensure controls remain effective. This may include temperature checks, outlet flushing, inspection of tanks, monitoring of sentinel outlets and reviewing usage patterns across the building.
Accurate records are essential. They demonstrate that checks have been completed, actions have been taken and responsibilities are being managed properly.
Records may include:
Buildings change over time. Occupancy levels, water usage, refurbishments, system alterations and periods of low use can all affect legionella risk.
Risk assessments and control measures should be reviewed when changes occur or where monitoring suggests that existing controls may no longer be suitable.
Some areas of commercial buildings are more likely to create legionella risks than others.
These may include:
Even simple systems require management if there is a potential risk.
Temperature control is one of the key methods used to manage legionella risk.
Legionella bacteria are more likely to grow where water is warm enough to support bacterial growth but not hot enough to kill bacteria. Poor temperature control, stagnant water and insufficient circulation can all increase risk.
Facilities teams should pay close attention to whether hot and cold water systems are operating as intended and whether monitoring records show any recurring concerns.
Low-use areas are a common issue in commercial buildings.
Meeting rooms, unused washrooms, vacant units, seasonal buildings or areas with changing occupancy can all create outlets where water remains stagnant for long periods.
Stagnant water can increase legionella risk, particularly where flushing is inconsistent or not recorded.
This is why a planned flushing regime is often an important part of legionella control, especially in buildings where occupancy changes frequently.
Legionella management is closely linked to health and safety compliance. HSE guidance, including ACOP L8 and HSG274, sets out expectations for managing the risk from legionella in water systems.
For dutyholders, compliance is about being able to show that risks have been assessed and suitable control measures are in place.
A good management programme helps demonstrate:
This provides reassurance for building owners, occupiers, staff, visitors and regulators.
Failing to manage legionella risk can have serious consequences.
The most important concern is the potential impact on health. Legionnaires’ disease can be severe, particularly for older people, smokers, those with underlying health conditions or anyone with a weakened immune system.
Poor management can also lead to:
For commercial properties, prevention is always better than emergency response.
Legionella control requires consistency, clear processes and reliable management. This is where the right facilities management support can make a real difference.
We support our clients with the management and prevention of legionella risk through a practical, joined-up approach to building compliance and maintenance.
This may include support with:
Our role is to help clients stay ahead of issues, maintain safer buildings and ensure essential checks are not missed.
Legionella management should not be reactive.
By the time concerns arise, the risk may already have developed. A proactive approach allows facilities managers and property teams to identify weaknesses early, maintain control measures and reduce the likelihood of more serious issues.
Regular monitoring, clear records and reliable maintenance all help keep water systems safer and better managed.
If you are responsible for a commercial property, it is worth asking:
If the answer to any of these is unclear, it may be time to review your current arrangements.
Legionella management is an important part of responsible facilities management. It protects building users, supports compliance and helps organisations maintain confidence in the safety of their premises.
With the right systems, monitoring and support in place, legionella risk can be managed effectively.
If you need support reviewing your water hygiene arrangements or managing legionella control across your site, we can help.
info@thefmcompanyuk.co.uk 01484 507986
This article is intended as general guidance only and should not be taken as legal advice. Dutyholders should refer to current HSE guidance and seek competent advice where required.
