Legionella risk assessment for landlords: a proportionate GB guide

Landlords should assess whether a property's water system could expose tenants or others to legionella and take proportionate steps to control any real risk. A simple domestic system with regular water use may need only a straightforward assessment and basic management. A complex, stored or intermittently used system can require more detailed expertise and controls. HSE's landlord guidance expressly says a domestic landlord's duty to assess does not automatically require an in-depth survey, routine sampling, a fixed annual reassessment or a “legionella test certificate”.

This guide is for Great Britain domestic rental accommodation. It helps the landlord decide what to inspect, record, explain to tenants and revisit. It is different from a copyable legionella risk assessment template, which should hold site-specific findings, and from a specialist written control scheme for a larger or more complex water system. If the proposed template route is not yet live, integration must only link it when the route exists.

What is the landlord actually assessing?

Legionella bacteria can grow in man-made water systems under favourable conditions. People can be exposed by breathing in contaminated water droplets. HSE identifies factors such as warm water, storage or recirculation, debris and aerosol generation. In a home, a shower is a relevant aerosol outlet; a rarely used room or long vacancy can allow water to stagnate. The question is not merely “does the property have a boiler?” It is whether the actual hot and cold water arrangement can allow growth and exposure and whether existing controls remain effective.

Start with the system as installed: mains or stored cold water; instantaneous heater or cylinder; tanks, distribution pipework and unused branches; showers, taps and other outlets; occupation and use patterns; and people who might be more vulnerable. HSE's HSG274 Part 2 covers residential accommodation and says all water systems require a risk assessment, but not all need elaborate measures. For many small homes with high water turnover, a simple assessment may conclude that the risk is low and appropriately controlled.

This is a water-safety task, not the same as a gas safety check. A Gas Safe record cannot stand in for an assessment of the water system. Conversely, a legionella assessment is not a test certificate or a promise that no bacteria are present.

A practical landlord assessment sequence

1. Identify who controls the system

Record the property, landlord, managing agent and person who can authorise maintenance. If an agent is appointed, specify in the management contract who assesses risk, communicates tenant instructions and responds to defects. HSG274 Part 2 says responsibility follows control of the premises/water system and that unclear contract allocation commonly leaves it with the landlord. A contractor can perform the assessment on the landlord's behalf, but a purchase order alone is not a control plan.

2. Describe the actual water system

Walk or commission a competent inspection. Note the water source, storage, heaters, pipework that can be seen, showers, outlets that are seldom used and any temperature-control or anti-scald devices. Obtain drawings or service information if available; label assumptions and inaccessible areas. Ask how the property is used: full-time home, student housing empty in summer, holiday accommodation with variable occupancy, or a room let within an occupied house. Water movement is often different across these cases.

3. Identify plausible growth and exposure points

Look for stored or tepid water, long pipe runs, poorly fitting tank lids, dead legs/redundant pipework, stagnant outlets, showers and reports of poor hot-water performance. Consider residents who may be more susceptible, while respecting privacy and avoiding unnecessary collection of medical details. HSE's risk-identification guidance asks whether people could breathe contaminated droplets and whether some may be more susceptible. Do not rely only on a score produced by a generic form; explain what was actually observed.

4. Decide controls that match the risk

For many domestic systems, controls can be simple: keep hot water hot, cold water cold and water moving; flush before a new letting after vacancy; ensure a stored cold-water tank is appropriately covered; address redundant pipework; and tell tenants how to report hot-water problems and maintain showerheads. HSE's landlord page gives these as examples. Any target temperature or technical adjustment must be selected for the particular system with competent advice, including the competing scald risk. Do not tell a tenant to change a cylinder control without an approved instruction. Where a risk is not adequately controlled by simple measures, get a competent water-safety professional to design, implement and verify a suitable plan.

5. Record the decision and review on change

Keep a proportionate record of the system, risk factors, findings, controls, responsibility, tenant information and review trigger. HSE says a domestic landlord is not necessarily under a statutory duty to write down the findings unless the five-or-more-employees threshold for employer records applies, but a written record is prudent evidence and operationally useful. HSE also says the law does not prescribe an annual or biennial domestic-landlord review. Revisit when the water system, occupancy, vacancy pattern, complaints or controls change, and periodically check that assumptions still hold. A specific follow-up date should come from the assessment, not a universal marketing rule.

Domestic examples that lead to different actions

These are examples, not diagnoses. A combi boiler does not eliminate all legionella risk, and a tank does not automatically mean sampling is necessary. HSE says the risk in many domestic systems is low because of regular turnover, and testing is not usually required for domestic hot and cold water systems. A specialist may recommend sampling in a specific case; the decision should be based on the system and risk assessment rather than a blanket sales package.

Vacancy, tenants and managing agents

Vacancy changes the water-flow assumptions. HSE advises considering a suitable flushing regime or other measures such as draining a system during long non-occupancy. Record who can access the property, which outlets are covered, the interval determined by the assessment and the safe reinstatement plan. A line reading “flush weekly” without a responsible person is weak evidence. A building with complex systems may need a specialist scheme rather than a simple caretaker instruction.

Give tenants practical, limited information: whom to contact when hot water is not heating properly, whether showerheads should be regularly cleaned, and any property-specific measure they should maintain. HSE includes these examples. Do not transfer the landlord's system assessment or specialist maintenance responsibility wholesale to tenants. If a tenant cannot access a control or does not have technical information, they cannot reasonably operate it.

With an agent, put obligations in the management agreement and preserve actual evidence: the assessment, water-system description, instructions sent, reported faults, work orders and follow-up. An agent status labelled “done” does not prove a cold-water tank was inspected or a fault was fixed. Make clear who can authorise a specialist visit and how high-risk findings escalate.

When to seek a specialist

Ask for competent help when the water system is complex, the landlord cannot describe it confidently, the assessment finds a potential uncontrolled exposure, the building has centralised or stored systems requiring technical controls, a vulnerable population is involved, or monitoring results/complaints suggest the current measures are not working. HSE says most domestic landlords may assess simple systems themselves if competent, and can appoint someone if they do not feel competent. Competence is about understanding the system and suitable controls, not purchasing a certificate bearing a particular logo.

Be careful with temperature advice. HSE uses temperature control as an important method, but a landlord must consider scald prevention, equipment design and the correct control points. A form cannot establish the measured temperature of an inaccessible pipe or prove the balance between legionella and scald risks. Where there is uncertainty, use a qualified water-safety/heating professional and retain the decision.

Common myths and avoidable mistakes

• “Every landlord must buy an annual legionella certificate.” HSE says health and safety law does not require a legionella test certificate and does not prescribe an annual or biennial review for domestic landlords.
• “Every property needs laboratory sampling.” HSE says sampling is not usually required for domestic hot and cold water systems; exceptional cases depend on the assessment.
• “A small home cannot have a risk.” A low-risk conclusion still needs a reason and review if conditions change.
• “The agent deals with it, so no one needs to know the system.” The contract and evidence route should identify responsibility.
• “Tenants can manage all water controls.” Give clear user actions while keeping the landlord's system and maintenance duties with the responsible party.
• “One stock form proves the water is safe.” The assessment must match actual storage, outlets, use and defects.

The most useful output is a short, intelligible decision: what system exists, what could cause exposure, why the chosen controls are proportionate, who will act and what change triggers review. A long document with boilerplate and no water-system facts is weaker than a short accurate assessment.

Where Complys may fit

The Complys legionella compliance page is the relevant commercial destination for asking about a document/maintenance workflow, but exact live product functions must be verified against implementation and current terms before the proposed page makes feature claims. Do not imply software samples water, certifies a system, calculates every review interval or replaces a competent assessor. The landlord remains responsible for the physical controls and follow-up. The companion template should be linked only after its route and content pass independent review.

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