Legionella Risk Assessment for Flats: A Complete Guide
A comprehensive guide to legionella risk assessment flats for freeholders, managing agents, and leaseholders. Understand your obligations under the HSE Approved Code of Practice L8, learn whether a legionella risk assessment for landlords is mandatory, and discover how a professional managing agent protects residents from Legionnaires' disease by managing water hygiene across your block. Whether you are a freeholder seeking clarity on legionella risk assessment cost or a leaseholder wanting to know what is a legionella risk assessment, this guide covers everything you need to know.
What Is a Legionella Risk Assessment?
A legionella risk assessment is a systematic evaluation of a building's water systems designed to identify conditions that could allow legionella bacteria to grow and spread. Legionella bacteria are naturally present in freshwater environments but become dangerous when they multiply in artificial water systems where temperatures are between 20 and 45 degrees Celsius, nutrients such as rust, scale, and biofilm are present, and water droplets or aerosols can be inhaled by building occupants. When contaminated water is inhaled, it can cause Legionnaires' disease - a severe and potentially fatal form of pneumonia that is particularly dangerous for elderly residents, those with weakened immune systems, and smokers.
In blocks of flats, the water systems that require assessment include communal cold water storage tanks, hot water cylinders and calorifiers, distribution pipework serving multiple units, header tanks, expansion vessels, showers, taps, and any other outlets that generate water droplets. The assessment examines the design, condition, and operation of these systems to determine whether the conditions for legionella growth exist and what control measures are needed to prevent contamination. A competent assessor will inspect all accessible components, measure water temperatures at key points, identify dead legs and infrequently used outlets, assess the condition of storage tanks and pipework, and evaluate the effectiveness of any existing controls.
Understanding what is a legionella risk assessment is the first step for any freeholder, managing agent, or leaseholder responsible for a block of flats. The assessment produces a written report that records the findings, identifies the risks, and sets out a programme of control measures - including temperature monitoring, flushing regimes, cleaning schedules, and any remedial works needed to bring the system into a safe condition. This report forms the foundation of the building's ongoing legionella management programme.
For a detailed overview of how we carry out legionella risk assessments across all types of residential blocks, visit our legionella risk assessment service page. Our approach to legionella risk assessment flats is thorough, compliant with HSE guidance, and designed to protect residents while keeping your building fully lawful.
Legal Requirements for Blocks of Flats
The legal framework governing legionella control in blocks of flats is set out in several key pieces of legislation and guidance. The Health and Safety at Work etc. Act 1974 places a general duty on employers and those in control of premises to ensure, so far as is reasonably practicable, the health and safety of people who may be affected by their activities. The Control of Substances Hazardous to Health Regulations 2002 (COSHH) require the identification and control of risks from hazardous substances, including legionella bacteria in water systems.
The most directly relevant guidance is the HSE Approved Code of Practice L8, known as ACoP L8, titled "Legionnaires' disease: The control of legionella bacteria in water systems." This document sets out the duties of those responsible for the control of legionella bacteria in water systems and provides practical guidance on how to comply with the law. ACoP L8 applies to all premises where water is stored or distributed and where there is a reasonably foreseeable risk of legionella exposure. For blocks of flats, this means any building with communal water storage, shared hot water generation, or distribution pipework serving more than one unit.
Is a legionella risk assessment mandatory for landlords? The answer is unequivocally yes. ACoP L8 requires the duty holder - typically the freeholder or managing agent - to identify and assess the risk of legionella in the water systems under their control. This means arranging a legionella risk assessment for landlords and duty holders, implementing the control measures recommended by the assessment, appointing a competent person to help with compliance, and keeping records of the assessment, monitoring, and any remedial actions taken. The HSE can take enforcement action against any duty holder who fails to carry out a risk assessment or implement adequate controls, including issuing improvement notices, prohibition notices, and pursuing criminal prosecution.
While some landlords search online for a legionella risk assessment template to carry out the work themselves, ACoP L8 is clear that the assessment must be conducted by a competent person with sufficient training and experience. A generic template is no substitute for a site-specific assessment by a qualified water hygiene specialist. For further information on how legionella compliance fits within the broader health and safety framework for your building, see our health and safety compliance page.
Who Is Responsible for Legionella in a Leasehold Block?
Establishing who holds the legal responsibility for legionella control in a leasehold block of flats is essential for freeholders, managing agents, and leaseholders. The question of whether do landlords have to do a legionella risk assessment is answered clearly by ACoP L8: the duty holder is the person or organisation that has an obligation to maintain and repair the water systems in the building. In most leasehold structures, this is the freeholder, who is legally responsible for the communal water infrastructure and must ensure it is assessed and managed to prevent legionella risks.
The Freeholder
The freeholder is the primary duty holder for legionella control in the communal parts of a block of flats. As the owner of the building structure and common areas, the freeholder is responsible for ensuring that a legionella risk assessment for landlords is carried out on all communal water systems, that control measures are implemented, and that ongoing monitoring is maintained. Even where a managing agent or RTM company is appointed to manage the building, the legal duty remains with the freeholder. For a full overview of these duties, see our freeholder responsibilities guide.
The Managing Agent
In practice, most freeholders appoint a professional managing agent to handle the day-to-day administration of legionella compliance. The managing agent arranges the risk assessment, instructs competent water hygiene consultants, implements control measures, maintains monitoring records, and ensures that any remedial works identified by the assessment are completed without delay. While the agent acts on behalf of the freeholder, a failure by the agent to discharge these duties properly can expose both parties to enforcement action from the HSE. Learn more about agent obligations on our managing agent responsibilities page.
What Leaseholders Should Know
Leaseholders who own and occupy their flat are generally responsible for water systems within their own property, such as individual boilers, showers, and taps. However, communal water systems - including shared cold water tanks, calorifiers, and distribution pipework - are the responsibility of the freeholder or managing agent. Leaseholders have the right to request evidence that a legionella risk assessment flats assessment has been carried out and that the building's water systems are being properly managed. The cost of the assessment and ongoing monitoring is typically included in the service charge. For details on these and other rights, visit our leaseholder rights guide.
If you are unsure whether your block has a current legionella risk assessment, or if you are concerned that your building's water systems are not being properly managed, your managing agent should be your first point of contact. A competent agent will hold copies of the current assessment and monitoring records and can provide these on request.
How Your Managing Agent Manages Legionella Risk
A professional managing agent plays a central role in ensuring that legionella risk assessment flats obligations are met consistently and without gaps. Legionella compliance is not a one-off task; it requires a systematic approach to assessment, monitoring, contractor management, record keeping, and communication with residents. At Block, our approach to legionella risk assessment management is built on the following commitments.
- Commissioning a comprehensive legionella risk assessment by a competent water hygiene consultant, with assessments reviewed every two years or sooner if changes to the water system occur
- Implementing a water temperature monitoring programme with monthly checks at sentinel outlets to ensure hot water is stored at 60 degrees Celsius or above and distributed at 50 degrees Celsius or above, and cold water is maintained below 20 degrees Celsius
- Establishing flushing procedures for infrequently used outlets and dead legs, with weekly flushing schedules maintained and documented to prevent water stagnation
- Arranging remedial works identified by the risk assessment, including descaling showerheads, replacing corroded pipework, removing dead legs, and cleaning or replacing cold water storage tanks
- Maintaining comprehensive records of all risk assessments, temperature monitoring results, flushing logs, remedial works, and contractor certifications in full compliance with ACoP L8 requirements
- Annual inspection of cold water storage tanks to check for contamination, correct lid fitting, insulation, and the absence of debris or biological growth
Legionella risk management sits within our broader health and safety compliance framework, which covers all statutory obligations for blocks of flats including fire safety, gas safety, electrical testing, and asbestos management. By managing all compliance disciplines through a single coordinated system, we eliminate the risk of gaps or overlaps and provide freeholders with a clear, auditable record of their building's compliance status.
The legionella risk assessment cost and the cost of ongoing monitoring, flushing, and any necessary remedial works in the communal areas are recoverable through the service charge. We budget for these costs transparently so that leaseholders can see exactly what they are paying for and why. Proper budgeting avoids unexpected demands and ensures that your building's water systems are maintained to a safe standard year after year.
Frequently Asked Questions About Legionella Risk Assessments in Flats
Do landlords have to do a Legionella risk assessment?
Yes, landlords have a legal duty to assess and control the risk of legionella in water systems under the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002. The HSE Approved Code of Practice L8 and supporting guidance document HSG274 make clear that all landlords, including freeholders and managing agents of blocks of flats, must carry out a legionella risk assessment of the water systems in any property they are responsible for. This applies to communal water systems in blocks of flats such as cold water storage tanks, hot water cylinders, calorifiers, and any shared distribution pipework. Failure to comply can result in enforcement action from the Health and Safety Executive, including prohibition notices, improvement notices, and criminal prosecution.
What should be included in a Legionella risk assessment?
A legionella risk assessment should include a thorough examination of the entire water system, identifying all potential sources of legionella bacteria and evaluating the controls in place to prevent bacterial growth. The assessment must cover the cold water storage arrangements, hot water generation and distribution systems, water temperatures throughout the system, the condition of pipework and fittings, the presence of any dead legs or infrequently used outlets, the effectiveness of any existing control measures such as temperature management and disinfection, and the general cleanliness and maintenance of tanks, calorifiers, and other system components. The assessment must also identify who is at risk, including residents, visitors, and maintenance personnel, and recommend any corrective actions needed to reduce the risk to an acceptable level. A written record of the assessment must be kept and reviewed regularly.
What is a Legionella risk assessment?
A legionella risk assessment is a systematic evaluation of a building's water systems to identify and assess the risk of legionella bacteria growth and the potential for people to be exposed to contaminated water droplets. Legionella bacteria thrive in water temperatures between 20 and 45 degrees Celsius and can cause Legionnaires' disease, a serious and potentially fatal form of pneumonia. The assessment examines all water systems within a building, including hot and cold water storage, distribution pipework, showers, taps, cooling towers, and any other systems that create water droplets or aerosols. In blocks of flats, the assessment focuses on communal water systems such as cold water storage tanks, shared hot water plant, and distribution pipework serving multiple units. The purpose of the assessment is to determine what controls are needed to prevent or minimise the risk of legionella contamination.
Can you do a Legionella risk assessment yourself?
While there is no legal requirement for the person carrying out a legionella risk assessment to hold a specific qualification, the HSE Approved Code of Practice L8 states that the assessment must be carried out by a competent person. A competent person is defined as someone with sufficient training, knowledge, and experience to identify the hazards and assess the risks associated with legionella in water systems. In practice, this means that most landlords, freeholders, and managing agents should appoint a specialist water hygiene consultant or a legionella risk assessment company with demonstrable competence and relevant industry accreditations. Attempting to carry out the assessment without the necessary expertise risks producing an inadequate assessment that fails to identify significant hazards, which could leave the duty holder exposed to enforcement action and, more importantly, put residents at risk of Legionnaires' disease.
How much should a Legionella risk assessment cost?
The cost of a legionella risk assessment varies depending on the size and complexity of the water system, the number of outlets, the type of building, and the location. For a small block of flats with a simple water system, a legionella risk assessment may cost between one hundred and fifty and three hundred pounds. Larger blocks with more complex communal water systems including cold water storage tanks, calorifiers, and extensive distribution pipework can expect to pay between three hundred and eight hundred pounds or more. These costs are typically recoverable through the service charge as a legitimate health and safety compliance expense. It is important to obtain quotations from reputable water hygiene specialists who are members of the Legionella Control Association and can demonstrate relevant experience in assessing residential blocks. The cheapest quotation is not always the best; a thorough assessment by a competent assessor provides far greater value than a superficial tick-box exercise.
How often do we need a Legionella risk assessment?
The HSE Approved Code of Practice L8 recommends that a legionella risk assessment should be reviewed regularly and at least every two years. However, the assessment must also be reviewed whenever there is reason to suspect it is no longer valid, such as after changes to the water system, a change in the use of the building, the results of monitoring indicating a loss of control, or a case of Legionnaires' disease or legionella contamination being identified. For blocks of flats, it is good practice to schedule a full reassessment every two years and to carry out an interim review annually to confirm that all control measures remain in place and effective. Between formal assessments, ongoing monitoring including monthly water temperature checks, quarterly flushing of little-used outlets, and annual inspections of cold water storage tanks should be maintained as part of the building's legionella management programme.
Expert Legionella Risk Assessment for Your Block
Whether you need help with a legionella risk assessment flats compliance programme, require a legionella risk assessment for your building's communal water systems, or are looking for a managing agent that takes health and safety compliance seriously, Block is here to help. We manage legionella risk for blocks of all sizes across England and Wales, ensuring full compliance with ACoP L8 and HSE guidance. As a legionella risk assessment for landlords specialist, we deliver thorough assessments, ongoing monitoring, and complete peace of mind.