Legionella Risk Assessments: A Guide for UK Landlords | LegalDocuments.co.uk
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If you let property or manage a building with a water system, keeping Legionella under control is one of those quiet obligations that rarely gets attention until something goes wrong. Legionnaires' disease is a serious form of pneumonia caused by inhaling tiny water droplets carrying Legionella bacteria, and the Health and Safety Executive expects those responsible for premises to take sensible, proportionate steps to prevent it.
For most residential landlords, that means carrying out a risk assessment, putting straightforward controls in place, and keeping a written record you can actually find when asked. This guide walks through what a Legionella risk assessment typically covers, why documentation matters, and how to build a record that stands up to scrutiny.
It is written for landlords, letting agents, and small property managers in England and Wales who want to get this right without overcomplicating it.
Overview
A Legionella risk assessment is a written examination of your property's water system designed to identify where Legionella bacteria could grow and spread, and what you are doing to stop that happening. The duty sits within the broader health and safety framework, primarily the Health and Safety at Work etc.
Act 1974 and the Control of Substances Hazardous to Health Regulations 2002 (COSHH), with practical direction set out in the HSE's Approved Code of Practice L8 and guidance document HSG274. For most domestic rented properties, the assessment is relatively simple. Typical housing stock with standard mains-fed systems, combi boilers, and regularly used taps presents a low risk, but 'low risk' is not the same as 'no duty'.
You still need to assess, record what you found, and keep the assessment under review. Larger, more complex premises such as houses in multiple occupation, purpose-built blocks with communal storage tanks, or commercial buildings with cooling towers, spa pools or rarely used outlets require a more detailed approach and, in many cases, a competent third-party assessor.
Key steps
- Gather information about the property and water system. Before you can assess anything, you need a clear picture of how water enters, moves around, and leaves the building. Note the address, the type of property, whether it is mains-fed or tank-fed, where hot water is generated, and which outlets exist. Include showers, taps, outside taps, and any unusual fittings.
- Identify the hazards specific to your system. Walk through the property with your notes and look for the conditions Legionella thrives in: water temperatures between roughly 20°C and 45°C, stagnation, scale, sediment, and spray-producing outlets like showers. Flag dead legs, little-used bathrooms, storage tanks without tight-fitting lids, and any area where water sits undisturbed.
- Evaluate the level of risk. Weigh the hazards you have identified against who uses the property and how often. A family home occupied year-round with a modern combi boiler and daily use of all outlets is typically low risk. A void property, a holiday let between bookings, or a building with a cold water tank and vulnerable occupants sits higher up the scale and deserves closer attention.
- Put proportionate control measures in place. Record what you are doing to manage the risks you found. Common measures include keeping hot water stored above 60°C and delivered above 50°C, keeping cold water below 20°C, flushing little-used outlets weekly, descaling shower heads periodically, and ensuring tanks are insulated and covered. Tenants should be given simple written instructions on flushing after absences.
- Record, review, and act on changes. Write the assessment up in a format you can share and revisit. Review it whenever the water system is altered, after major works, if occupants change significantly, or if there is reason to suspect the controls are not working. A dated, signed document with any follow-up actions clearly logged is far more useful than a glossy report gathering dust.
Common questions
Q Do I legally need a Legionella risk assessment for a standard rental property?
Yes. Landlords in England and Wales have a duty under health and safety law to assess the risk of Legionella in rental properties and take reasonable steps to control it. For most typical domestic lets the assessment is short and straightforward, but it must still be carried out and recorded. The HSE has confirmed that a simple written record is expected, even for low-risk properties.
Q How often should the risk assessment be reviewed?
There is no fixed statutory interval, but the assessment should be reviewed whenever circumstances change in a way that could affect the risk. Typical triggers include changes to the water system, a new boiler, extended void periods, building works, or a change in how the property is used. Many landlords also build in a routine review every two years as a matter of good practice.
Q Can I carry out the assessment myself, or do I need a specialist?
For a standard low-risk residential property, a landlord or agent who has read the relevant HSE guidance and understands the system can reasonably carry out the assessment themselves. For larger buildings, HMOs, properties with stored water, cooling systems, or any premises where you are unsure, it is sensible to instruct a suitably competent external assessor.
Q What should tenants be told about Legionella?
Tenants benefit from simple, plain-English instructions on the few things they can do to reduce risk. This typically includes running taps and showers after the property has been empty for a while, cleaning shower heads if scale builds up, and reporting problems with heating or hot water. A short note included with the tenancy paperwork is usually enough.
Q Is a certificate from a contractor the same as a risk assessment?
Not necessarily. A contractor's test certificate or water sample result records a specific check at a specific moment. A risk assessment is a broader written document describing the system, the hazards, the controls, and who is responsible. You may hold both, but one does not replace the other.
Q What happens if something goes wrong and I have no assessment on file?
Failing to assess and manage Legionella risk can expose landlords to enforcement action under health and safety legislation, as well as civil claims if a tenant becomes ill. Having a dated, sensible written assessment on file is one of the strongest pieces of evidence that you took your duty seriously, even where the actual risk in the property was low.
Sources
This guide is based on primary UK law and official guidance.
- Guidance · UK GovHSE: Legionnaires' disease guidancehse.gov.uk
- Guidance · UK GovHSE Approved Code of Practice L8hse.gov.uk
- Guidance · UK GovHSE HSG274: Technical guidance on Legionella controlhse.gov.uk
- LegislationHealth and Safety at Work etc. Act 1974legislation.gov.uk
Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.