If you let a straightforward one-bedroom flat, Legionella control may feel relatively simple. Add several tenants, a cold-water storage tank, multiple bathrooms or a property sitting empty between tenancies, and the picture changes quickly.
The practical question is not simply, “Do I have a Legionella risk assessment?” It is, “Does my assessment reflect how the water system is actually used?”
For landlords, that means looking closely at temperatures, stagnation, showers, little-used outlets, records and the person responsible for keeping everything under control. This guide explains how a Legionella risk assessment for landlords works in the real world, particularly for HMOs, stored-water homes and vacant properties.
Why property use matters more than the property label
Legionella risk is influenced by the design and use of a water system. The number of occupants, the length of time outlets remain unused and the presence of stored water can all affect the assessment.
A modern flat with a combi boiler and regular daily use may have a different risk profile from:
- An HMO with several bathrooms and shared facilities
- A house with a cold-water storage tank or hot-water cylinder
- A property that remains empty for several weeks
- A rental with an ensuite shower that is rarely used
- A property with long pipe runs, redundant outlets or “dead legs”
This is why a generic checklist is rarely enough. Your assessment should consider the actual layout, equipment and occupancy pattern rather than simply ticking a box marked “rental property”.
That practical detail is what makes a risk assessment useful.
Legionella assessment for an HMO landlord: what changes?
An HMO usually has more outlets, more occupants and more opportunities for parts of the system to receive inconsistent use. One tenant may shower every morning. Another may spend most of the week away. A spare ensuite may barely be used at all.
That variation matters.
A legionella assessment for an HMO landlord should normally identify:
- The location and type of water storage tanks and hot-water cylinders
- The boiler, cylinder and distribution pipework
- Shared bathrooms, ensuites, kitchens and utility areas
- Showers and other outlets that can create an aerosol
- Little-used taps, showerheads and toilets
- Redundant pipework or dead legs
- Areas where hot or cold water may remain within an unsuitable temperature range
- The person responsible for monitoring and recording control measures
The assessment should also consider whether residents understand what to do with little-used outlets. For example, a shower in an occasionally occupied room may need a clear flushing arrangement rather than being ignored until the next tenant moves in.
More tenants do not automatically mean a serious Legionella problem. However, more outlets and more complicated usage patterns mean there is more to inspect and manage. That is where a detailed assessment earns its keep.
Stored water: focus on temperature and circulation
Properties with stored water need particular attention because water can remain in tanks, cylinders and pipework for longer periods.
Legionella bacteria can multiply in favourable conditions, particularly where water is warm but not hot enough to control bacterial growth. As a general guide, the range between 20°C and 45°C is treated as a significant growth range.
Your control measures should therefore establish whether:
- Stored hot water reaches approximately 60°C
- Hot water is distributed effectively through the system
- Sentinel outlets reach suitable temperatures within a reasonable running time
- Cold water remains suitably cool, normally below 20°C
- There are sections of pipework where water becomes trapped or remains unused
- Showerheads and taps require cleaning or descaling
These figures are not an invitation to adjust a boiler without considering scalding risk. Hot-water controls must balance Legionella prevention with tenant safety, particularly in HMOs, properties occupied by vulnerable people and homes where children may be present.
The assessment should explain what needs checking, how often checks take place and who records the results. A temperature reading with no date, location or follow-up action is not a particularly helpful record. It is more of a loose fact wearing a clipboard costume.
Vacant properties need an active plan
A property that sits empty is not necessarily a lower-risk property. In fact, low use can create a specific challenge because water may stagnate in tanks, pipework, taps and shower fittings.
This is particularly relevant when:
- A tenancy ends before a replacement tenant is found
- A property is undergoing refurbishment
- A landlord holds a property between sales or lettings
- An HMO room is empty while other rooms remain occupied
- A property is closed during holidays or seasonal periods
Your Legionella risk assessment should explain what happens during vacancy. Do not rely on a general instruction such as “flush before occupation”. Set out who does it, which outlets are included and how the activity is recorded.
A risk-based flushing routine may include running outlets throughout the property, including little-used taps and showers. Showers require additional care because running them can create aerosols. Follow the control scheme, avoid unnecessary splashing, ventilate the area and use appropriate precautions.
Before reoccupation, consider whether:
- All outlets have been flushed
- Cold water runs cool after an appropriate period
- Hot water reaches the required temperature
- Showerheads and taps need cleaning or descaling
- Any unusual temperature or flow issue requires investigation
- The flushing or pre-tenancy checks have been recorded
There is no single flushing timetable that suits every rental property. A compact flat with daily use is not managed in the same way as a large vacant HMO with stored water. The important point is to identify the risk and apply a documented, proportionate response.
Who is competent to complete the assessment?
A landlord may appoint themselves as the responsible person, particularly where the system is simple and they have enough knowledge, training and experience to manage it properly.
However, being the owner does not automatically make someone competent. You need to understand the system, recognise potential risk factors, arrange appropriate controls and know when specialist support is required.
An HMO landlord, property manager or letting agent should be especially cautious where the property includes:
- Several bathrooms or kitchens
- Stored hot or cold water
- Complex or extended pipework
- Vulnerable occupants
- Repeated temperature problems
- Long vacancy periods
- A history of plumbing alterations
- Unclear responsibility between landlord, agent and contractor
A competent assessor should be able to inspect the system, identify risks, recommend practical control measures and produce clear documentation. They should also explain what the landlord or managing agent needs to do after the assessment.
The assessment itself is not the end of the process. It is the starting point for sensible management.
Keep records that someone else can understand
Good Legionella management depends on records that are accurate, current and easy to follow.
Keep the risk assessment alongside evidence of:
- Temperature checks
- Flushing during vacancy or low-use periods
- Showerhead and tap cleaning
- Plumbing repairs and alterations
- Remedial actions
- Contractor visits
- Reviews and changes to the control scheme
- The name of the responsible person
Record the date, location, result and action taken. If a temperature is outside the expected range, note what happened next. “Checked” is not enough if the check identifies a problem that then disappears into a drawer.
This documentation also helps when a property changes hands or a managing agent takes over. A new responsible person should not have to reconstruct the history from a collection of invoices, text messages and optimistic guesses.
Precise records make ongoing management easier and provide a clearer audit trail.
When should a landlord review the assessment?
A Legionella risk assessment should be reviewed regularly and whenever there is a reason to believe it may no longer be valid.
Review it when:
- You install or replace a boiler, cylinder, tank or shower
- Pipework is altered
- The number of occupants changes significantly
- A property becomes vacant for an extended period
- An HMO is converted, reconfigured or expanded
- A tenant reports inconsistent hot or cold water
- Temperatures repeatedly fall outside the expected range
- A new managing agent or responsible person takes over
- An incident or suspected exposure occurs
The review does not always require a completely new assessment. Sometimes a documented update is appropriate. The key is to ensure the paperwork matches the property as it exists today, not the property as it looked several tenancies ago.
Why London and Kent landlords benefit from meticulous local support
Since 2012, Evestaff Property Inventory Clerks has supported landlords, property managers and letting agencies across London and Kent with precision-focused property documentation.
Our experienced clerks use modern technology to produce clear, detailed reports that are practical to review and simple to share. That same meticulous approach matters when documenting Legionella risks, particularly in busy HMOs, multi-property portfolios and homes with unusual occupancy patterns.
Evestaff Property Inventory Clerks are accredited members of ECMK. This reinforces our focus on professional standards, careful reporting and dependable service.
Whether you manage one stored-water property or a portfolio of HMOs, make sure your risk assessment reflects the real-world use of each home. If you need help arranging a legionella risk assessment for landlords, contact Evestaff through propertyinventoryclerks.co.uk.
New customers can receive 10% off their first booking when booking directly. And if another landlord or property professional could benefit from a careful, reliable service, take a look at our Refer a Friend offer.
A practical landlord checklist for 2026
Before you consider the job complete, ensure you can answer “yes” to these questions:
- Does the assessment reflect the actual water system?
- Have you identified tanks, cylinders, showers, dead legs and little-used outlets?
- Are hot and cold-water temperatures being managed and recorded?
- Is there a written plan for vacant periods?
- Does the plan cover flushing before reoccupation?
- Is someone clearly appointed as the responsible person?
- Is that person genuinely competent to manage the risk?
- Are maintenance, cleaning, flushing and remedial actions documented?
- Will the assessment be reviewed after system or occupancy changes?
If the answer to any of these is “not yet”, that is the part to address next. Effective Legionella management is not about producing a report and filing it away. It is about understanding how water moves through the property and making sure the control measures continue to work in practice.
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