Legionella bacteria present a serious health risk in residential buildings, particularly where water hygiene management is neglected. For block managers, managing agents, and landlords, ensuring compliance with Legionella control regulations is both a legal duty and a key part of protecting residents and contractors.
This guide explains everything UK property managers need to know about Legionella risk assessments, legal responsibilities, and best practices for safe water management.
What Is Legionella?
Legionella is a bacteria that thrives in stagnant, warm water (between 20°C and 45°C). When tiny droplets containing the bacteria are inhaled—such as from showers, taps, or cooling systems—it can cause Legionnaires’ disease, a potentially fatal type of pneumonia.
Common residential sources include:
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Communal hot and cold water systems
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Water tanks and storage vessels
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Unused outlets (e.g. taps in vacant flats)
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Spa pools or communal showers
Who Is Responsible for Legionella Control?
Under the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health (COSHH) Regulations 2002, the responsibility falls on the dutyholder.
In residential blocks, this is usually:
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The freeholder
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A property or block management company
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A Right to Manage (RTM) company
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A Residents’ Management Company (RMC)
These parties are legally accountable for assessing and controlling Legionella risks in shared water systems and communal facilities.
Is a Legionella Risk Assessment Required?
Yes. A Legionella risk assessment is usually required, especially if:
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The property has a communal water tank or shared hot water system
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There are multiple flats sharing water services
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The water system is not regularly flushed or is poorly maintained
For more complex systems, a written scheme of control is also recommended.
What Does a Legionella Risk Assessment Involve?
A qualified contractor or competent person will:
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Inspect the water system – tracing hot and cold routes, identifying tanks, calorifiers, and dead legs.
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Check temperature controls – cold water must stay below 20°C, hot water above 50°C.
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Review usage patterns – identifying areas prone to stagnation (e.g. vacant flats).
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Assess cleanliness – checking for sludge, scale, debris, or biofilm.
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Identify risks – such as poor insulation or communal showers.
The findings are compiled into a risk assessment report, outlining risks, controls, and ongoing monitoring requirements.
Ongoing Legionella Control Measures
Following the assessment, routine controls may include:
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Temperature checks at sentinel outlets (e.g. furthest taps)
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Flushing little-used outlets (vacant flats, plant rooms)
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Tank cleaning and disinfection when necessary
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Logbook recording of checks, servicing, and maintenance
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Resident awareness, especially for vulnerable occupants
For communal water systems, monitoring is typically carried out monthly or quarterly, depending on the risk level.
Legal Implications of Non-Compliance
Failure to manage Legionella risks can result in:
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Enforcement action from the HSE
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Civil claims following illness or outbreaks
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Reputational damage with residents and leaseholders
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Criminal prosecution in severe cases (e.g. illness or death)
Best Practices for Block Managers
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✅ Arrange risk assessments by competent professionals
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✅ Review and update assessments every 2 years or after system changes
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✅ Maintain accurate records and logbooks
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✅ Partner with specialist water hygiene contractors for monitoring
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✅ Inform residents about precautions, e.g. after extended holidays
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Conclusion
Legionella control is not optional—it is both a legal requirement and a moral duty. Whether your building has a simple water system or a complex infrastructure, proactive risk management is vital.
Need Help With Legionella Compliance?
We provide:
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Professional Legionella risk assessments
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Ongoing monitoring services
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Bespoke water hygiene solutions for block management across the UK
👉 Contact us today to arrange a Legionella risk assessment or review your compliance status.