A Legionella Risk Assessment in London is an important part of managing water hygiene and protecting people from exposure to Legionella bacteria. Businesses, landlords, property managers, care facilities, hotels and other organisations with water systems should understand where Legionella risks may occur and what controls are needed to keep those risks under control.
Legionella bacteria can multiply in poorly managed water systems, particularly where water is stored, recirculated or allowed to become stagnant. People can potentially be exposed when contaminated water creates fine droplets or aerosols, such as those produced by showers, taps, cooling systems and spa facilities. The Health and Safety Executive (HSE) requires employers and those controlling premises to assess and manage reasonably foreseeable Legionella risks.
What Is a Legionella Risk Assessment?
A Legionella Risk Assessment in London is a systematic examination of a building's water systems to identify potential sources of Legionella exposure and determine appropriate control measures.
The assessment considers the design, condition and operation of water systems, including hot and cold water services, storage tanks, pipework, showers, pumps and other equipment. The HSE recommends that the assessment identifies potential risk sources, existing controls, monitoring and maintenance procedures, responsible persons and arrangements for reviewing the assessment.
The assessment does not simply involve testing water samples. It is a broader evaluation of how a water system operates and whether effective controls are in place.
Why Is Legionella Risk Assessment Important in London?
London contains a huge variety of commercial, residential and public buildings. Offices, hotels, care homes, schools, hospitals, leisure facilities, restaurants and residential properties can all have different water-system risks.
A properly completed assessment can help identify conditions that may encourage Legionella growth and provide recommendations for controlling those conditions.
It can help organisations:
- Identify potential Legionella hazards
- Understand their water systems
- Identify people who may be exposed
- Establish appropriate control measures
- Maintain suitable water temperatures
- Reduce water stagnation
- Identify redundant pipework
- Establish monitoring procedures
- Maintain appropriate records
- Review controls when circumstances change
The HSE states that employers and people in control of premises have duties to assess and manage sources of Legionella risk.
What Causes Legionella Risk?
Legionella bacteria can become a concern where water systems provide favourable conditions for bacterial growth. The HSE highlights several factors that should be considered during a risk assessment, including water temperatures between approximately 20°C and 45°C, stored or recirculated water, nutrients such as rust and sludge, biofilms, and conditions that allow water droplets to be produced.
Common risk factors include:
- Stagnant water
- Poor temperature control
- Low water usage
- Dead legs and redundant pipework
- Dirty or poorly maintained storage tanks
- Scale and sediment
- Biofilm formation
- Poorly maintained showers
- Certain cooling systems
- Spa pools and similar facilities
A competent assessment helps determine whether these conditions exist within a particular property.
Which Buildings May Need a Legionella Risk Assessment?
Legionella risk can occur in many types of premises. Examples include:
Offices
Large offices can have complex hot and cold water systems, multiple washrooms, kitchens and shower facilities. Low-use outlets can sometimes create additional management considerations.
Hotels
Hotels have numerous guest rooms, showers, baths and other water outlets. Changes in occupancy can affect water usage and increase the importance of appropriate monitoring and flushing procedures.
Care Homes
Care homes may require particular attention because some residents can be more susceptible to Legionnaires' disease. HSE guidance specifically highlights increased vulnerability in health and social care settings.
Schools and Educational Buildings
Schools may contain large water systems with periods of reduced use during holidays. Water-system management should take account of occupancy patterns and periods when outlets are not regularly used.
Residential Properties
Landlords also have responsibilities to assess and control Legionella risks associated with hot and cold water systems. HSE guidance explains that a simple assessment may sometimes demonstrate that risks are low and appropriately controlled, but the assessment should be reviewed if circumstances change.
Leisure Facilities
Swimming pools, spa pools, cooling systems and other water-based facilities may require specialist assessment and monitoring because they can create conditions where people are exposed to water droplets or aerosols.
What Does a Legionella Risk Assessment Include?
A professional assessment should be appropriate to the size and complexity of the water system.
1. Identifying the Water Systems
The assessor examines the building's hot and cold water systems and associated equipment. This can include storage tanks, calorifiers, pumps, pipework, showers, taps and other outlets.
2. Identifying Potential Hazards
The assessment looks for conditions that could encourage Legionella growth, including stagnant water, unsuitable temperatures, scale, sediment and poorly maintained equipment.
3. Identifying People at Risk
The assessor considers employees, residents, visitors, contractors and other people who could potentially be exposed.
Some individuals may be more susceptible because of factors such as age, illness or a weakened immune system.
4. Reviewing Existing Controls
Existing measures are assessed to determine whether they are appropriate and working effectively.
5. Checking Temperature Control
For hot and cold water systems, temperature is an important control measure. HSE guidance states that cold water should generally be maintained below 20°C where possible, while hot water should be stored at least at 60°C and reach 50°C at outlets within one minute. Healthcare premises have a 55°C outlet target in the relevant HSE guidance.
6. Reviewing Monitoring Procedures
The assessment considers whether temperatures, maintenance activities and other control measures are being monitored at appropriate intervals.
7. Producing Recommendations
If deficiencies are identified, the assessment should provide practical recommendations to improve control.
Legionella Control Measures
Once risks have been identified, appropriate control measures should be introduced.
Common measures include:
Temperature control: Maintaining hot water at appropriate temperatures and keeping cold water sufficiently cool.
Regular flushing: Infrequently used outlets may require regular flushing to reduce stagnation.
Cleaning and disinfection: Water systems should be kept clean, with cleaning and disinfection undertaken where required.
Removing redundant pipework: Unused pipework can create stagnant areas and should be considered during water-system management.
Maintenance: Tanks, showers, pumps and other equipment should be maintained appropriately.
Monitoring: Relevant temperatures and other control parameters should be monitored and recorded.
The HSE recommends designing, maintaining and operating water systems in conditions that prevent or adequately control Legionella growth.
Do You Need Legionella Water Testing?
Water testing is not automatically required for every hot and cold water system. The need for microbiological monitoring depends on the system and the outcome of the risk assessment.
HSE guidance states that routine microbiological monitoring is generally not required for typical enclosed hot and cold water systems, although testing may be appropriate where there is doubt about the effectiveness of controls or recommended temperatures or disinfection concentrations are not consistently achieved.
For systems where testing is appropriate, sampling should be performed correctly and samples should be tested by a suitable UKAS-accredited laboratory following the relevant guidance.
This is why a Legionella risk assessment should not be confused with a simple water test.
Legionella Risk Assessment and HSE Guidance
The HSE's L8 Approved Code of Practice provides guidance for dutyholders on controlling Legionella bacteria in water systems. It covers risk assessment, the role of the responsible person, control schemes, review of control measures and relevant responsibilities.
HSE's HSG274 technical guidance provides further practical information for different types of water systems, including hot and cold water systems, evaporative cooling systems and other risk systems.
A competent professional should understand the relevant guidance and apply it appropriately to the specific property rather than using a generic assessment for every building.
Written Control Scheme
Where a significant Legionella risk is identified that cannot be prevented, a written control scheme should describe how the risk will be managed.
According to HSE guidance, a control scheme can include a description or schematic of the system, responsibilities, safe operating procedures, control methods, monitoring arrangements and the frequency of checks.
Keeping clear records makes it easier to demonstrate that the control measures are being implemented and monitored.
How Often Should a Legionella Risk Assessment Be Reviewed?
There is no universal requirement that every Legionella risk assessment must simply be repeated at a fixed annual interval. Instead, it should be reviewed regularly and whenever there is reason to believe it may no longer be valid.
Reviews may be necessary following:
- Changes to the water system
- Building alterations
- Changes in occupancy
- Installation of new equipment
- Changes to water usage
- Extended periods of closure
- Significant maintenance work
- Identification of control failures
- Changes in the population at risk
The HSE recommends reviewing risk assessments and control arrangements to confirm that controls remain effective.
Choosing a Legionella Risk Assessment Company in London
When selecting a professional provider, businesses should look for suitable competence, experience and knowledge of water systems.
A good provider should be able to:
- Inspect the complete water system
- Identify potential Legionella hazards
- Produce a clear risk assessment
- Provide practical recommendations
- Explain required control measures
- Identify responsible persons and responsibilities
- Review monitoring arrangements
- Assist with ongoing compliance
- Provide appropriate documentation
The HSE advises dutyholders to check the competence of external contractors and consultants, including their experience, qualifications, training and relevant professional credentials.
Conclusion
A professional Legionella Risk Assessment in London can help businesses, landlords and property managers understand and control risks associated with water systems. The assessment should consider the building's water infrastructure, potential sources of Legionella exposure, people at risk, existing controls, monitoring procedures and maintenance requirements.
Effective Legionella management is an ongoing process. It involves appropriate system design, temperature control, cleanliness, maintenance, monitoring and regular review. A competent assessment provides the foundation for developing an effective control strategy and helps dutyholders meet their health and safety responsibilities.
FAQs
Is a Legionella risk assessment a legal requirement in London?
Employers and people in control of premises have legal duties to assess and manage reasonably foreseeable risks from Legionella. The assessment should be appropriate to the water system and circumstances of the premises.
2. Who is responsible for Legionella risk?
The person responsible for controlling Legionella risk is often called the responsible person. They should have sufficient authority, knowledge, skills and experience to manage the risks. The responsible person can be someone within the organisation or an appropriately competent external professional.
3. Do landlords need a Legionella risk assessment?
Landlords have health and safety duties relating to Legionella risks in relevant residential water systems. HSE guidance recommends assessing the risks and implementing proportionate control measures.
4. Does every property need Legionella water testing?
No. Routine microbiological testing is not normally required for typical enclosed hot and cold water systems. Whether testing is necessary depends on the system and risk assessment.
5. How often should a Legionella risk assessment be reviewed?
It should be reviewed periodically and whenever significant changes occur that could affect the validity of the assessment. Examples include changes to the water system, occupancy or control measures.
