Legionella risk assessment — Landlord obligations

England landlords have a legal duty under the Control of Substances Hazardous to Health (COSHH) Regulations 2002 and HSE guidance to assess and control the risk of legionella bacteria in their properties. Most standard domestic properties are low risk, but a written assessment must still be completed and kept on record. Reviewed March 2026.

What the rule is

The Health and Safety at Work etc. Act 1974 and COSHH Regulations 2002 place a duty on landlords to ensure their rental properties are safe. The HSE’s Approved Code of Practice (ACoP L8) and HSG274 guidance confirm that landlords must assess the risk of exposure to legionella bacteria and implement appropriate controls. This applies to all residential rental properties in England.

When it applies

• Before the first tenancy in a property
• When significant changes are made to the water system (new boiler, pipework)
• Periodically — the HSE recommends reviewing the risk assessment every 2 years or when circumstances change
• When there is a change in tenancy (particularly after a property has been unoccupied)

What landlords must do

• Identify and assess sources of risk — water systems including cold water tanks, hot water cylinders, pipework, showers, taps, and any features where water is stored or circulated
• Consider factors that increase risk: water temperatures between 20–45°C, long pipework runs, infrequently used outlets, scale and corrosion
• Implement appropriate controls — typically for standard domestic properties: ensure hot water is stored above 60°C, cold water is kept below 20°C, and all outlets are used regularly
• Record the assessment in writing and keep it on file
• Brief tenants on simple precautions (e.g. run taps for a minute after a period of absence)

What evidence to keep

• Written legionella risk assessment with the date completed
• Who carried out the assessment
• Any control measures put in place
• Any remedial works carried out
• Review dates and updated assessments

Common mistakes

• Assuming it’s only for commercial properties — HSE guidance explicitly covers residential rental properties
• No written record — a verbal assessment or informal check is not sufficient; you need a written document
• Ignoring the cold water tank — older properties with cold water storage tanks need particular attention
• Not reviewing after a void period — a property that has been empty for weeks is higher risk; flush all outlets before a new tenant moves in
• Thinking a new boiler eliminates the risk — risk depends on the whole water system, not just the boiler

FAQ

Who can carry out a legionella risk assessment? For most straightforward domestic properties, a competent landlord can carry out and record their own risk assessment using HSE guidance. For complex systems (large storage tanks, multiple outlets), consider a specialist water hygiene contractor.

What is a “simple” domestic property? A small property with a combi boiler (no storage cylinder or cold water tank), mains-fed cold water, and standard outlets is generally low risk. The HSE provides a straightforward checklist for landlords.

How often must the assessment be reviewed? HSE recommends reviewing every 2 years as a minimum, and whenever there are significant changes to the water system or the property.

What if I find a high-risk situation? Take corrective action — remediate the risk (e.g. insulate pipework, increase temperature settings, remove redundant pipework) and record what you did. Seek professional advice if the system is complex.

Is there a legal requirement to use a specialist contractor? No — for low-risk domestic properties, landlords can carry out their own assessment. However, using a specialist for the initial assessment and periodic reviews reduces risk and provides a professional record.