Legionella Risk Assessments Explained

A Legionella risk assessment checks your water system for conditions where Legionella bacteria could grow. Landlords and anyone in control of premises have a legal duty to assess the risk. Assessments are typically reviewed every two years, and you receive a written report with practical recommendations.

Legionella is a topic many property owners only think about when a letting agent, insurer, or auditor asks for a risk assessment. It is, however, a straightforward duty to meet once you understand what is involved. This guide explains what a Legionella risk assessment covers, who is responsible for arranging one, and how often it needs reviewing.

What Is Legionella?

Legionella is a type of bacteria that can grow in water systems. It becomes a health risk when water is stored or circulated at the wrong temperatures and then released as a fine spray or mist, for example from a shower, tap, or cooling system. Breathing in those droplets can cause Legionnaires' disease, a serious form of pneumonia.

The good news is that the conditions Legionella needs to grow are well understood and easy to check for. A risk assessment simply looks at your water system and identifies anywhere those conditions could exist, along with practical steps to control them.

Who Legally Needs an Assessment

Under the Health and Safety at Work Act and the associated Approved Code of Practice (ACoP L8), anyone in control of premises has a legal duty to assess and control the risk of Legionella in their water systems. In practice that includes:

• Landlords: Residential landlords have a duty to assess the risk in rental properties. It is one of the checks letting agents and tenants increasingly ask to see.
• Employers and business owners: Offices, shops, cafes, care homes, and other workplaces all fall within scope.
• Managing agents and facilities managers: Anyone responsible for the upkeep of a building's water system.

Meeting the duty does not have to be complicated. For most homes and smaller commercial properties, a single on-site assessment with a clear written report is all that is needed.

What an Assessment Involves

A Legionella risk assessment is an on-site survey of your water system carried out by a competent person. We look at how water is stored, heated, and used throughout the property, and check the points where risk can build up.

• Water storage and heating: We check hot and cold water temperatures, cylinders, and tanks to confirm water is stored and delivered at safe temperatures.
• Outlets and dead legs: We identify taps, showers, and any little-used or disconnected pipework where water can sit and stagnate.
• System layout and condition: We note the general condition of the system and anything that could increase risk, such as debris, scale, or unusual pipe runs.
• Practical recommendations: Where we find anything worth acting on, we set out clear, proportionate steps to control it.

How Often It Should Be Reviewed

There is no fixed legal interval, but the HSE recommends reviewing your assessment whenever there is reason to believe it may no longer be valid. For most properties that works out at roughly every two years, or sooner if anything significant changes, such as new pipework, a change of use, or a period where the property has been empty.

Keeping the assessment up to date is part of demonstrating that you have met your duty, which is exactly what an insurer or auditor will want to see.

What You Receive

At the end of the assessment you receive a full written risk assessment report. It documents what we found, highlights any risks, and lists the recommended control measures in plain English. You can keep it on file to show that the property has been assessed and that you are managing the risk responsibly.

If you would like to arrange an assessment, or you are not sure whether your property needs one, just give us a call. We are happy to talk it through.

Frequently Asked Questions