Legionella Risk Assessment

Legionella Risk Assessment: A Complete Guide to UK Compliance

A Legionella risk assessment is the single most important step you can take to protect your people from the dangers of Legionnaires’ disease and ensure you are compliant with UK health and safety law. It is the foundation of any effective water safety management programme.

This guide explains what a Legionella risk assessment is, why it is a legal requirement, and what the process involves.

What is a Legionella Risk Assessment?

A Legionella risk assessment is a systematic evaluation of the water systems within your premises to identify and assess the potential risks of Legionella bacteria growth and exposure. The goal is to pinpoint any conditions that could encourage the bacteria to multiply, create a breathable water aerosol, and expose individuals to harm.

The assessment provides a detailed report on the condition of your systems and a clear action plan of control measures required to minimise the risk and ensure you comply with the law.

Is a Legionella Risk Assessment a Legal Requirement?

Yes. For any premises where you are the employer or person in control (including landlords), a Legionella risk assessment is a legal requirement.

This duty is established under two key pieces of UK legislation:

The Health and Safety at Work etc. Act 1974

This places a duty on employers to protect the health and safety of their employees and anyone affected by their work, which includes tenants and visitors.

The Control of Substances Hazardous to Health (COSHH) Regulations 2002

These regulations classify Legionella bacteria as a “substance hazardous to health,” making it mandatory for employers and landlords to assess and control the risks of exposure.

Following the guidance in the Health & Safety Executive’s (HSE) Approved Code of Practice L8 is the most direct way to demonstrate that you are complying with these legal duties. The risk assessment is the first, essential step in this process.

The 5 Steps of a Professional Legionella Risk Assessment

Our qualified and experienced assessors follow a comprehensive, five-step process to ensure every potential risk is identified and a robust management plan is put in place.

Step 1: System Survey and Asset Register

The process begins by mapping out all water systems on your property. Our assessor will conduct a thorough physical inspection to identify all assets, including water entry points, storage tanks, water heaters, pipework, and outlets like taps and showers. This information is used to create a detailed asset register and schematic drawings of your system.

Step 2: Identifying Potential Hazards

The assessor systematically inspects the water systems for conditions that are known to encourage Legionella growth. This includes:

Water Temperature

Checking if water is being stored or circulated in the 20-45°C range where Legionella thrives.

Stagnation

Identifying areas where water could stagnate, such as in oversized storage tanks, infrequently used outlets, or redundant pipework (“dead legs”).

Nutrients

Looking for the presence of rust, sludge, scale, or biofilm, which provide a food source for the bacteria.

Aerosol Creation

Identifying any points where breathable water droplets could be created and dispersed, such as showers, cooling towers, or spa pools.

Step 3: Assessing the Level of Risk

Once hazards are identified, the assessor evaluates the overall level of risk. This involves considering the likelihood of exposure and the vulnerability of the people on the premises, such as the elderly, young children, or those with weakened immune systems.

Step 4: Recommending Control Measures

Based on the findings, the assessor will recommend a clear and proportionate set of control measures to mitigate the identified risks. These may include:

• – Adjusting temperature settings to ensure hot water is stored above 60°C and cold water below 20°C.
• – Implementing a flushing regime for little-used outlets.
• – Scheduling the cleaning and disinfection of water tanks and showerheads.
• – Recommending the removal of dead legs in pipework.

Step 5: The Risk Assessment Report & Logbook

You will receive a comprehensive report that details all findings, explains the risks, and provides clearly laid out instructions on how to manage them. This document forms the basis of your written scheme of control and provides the evidence needed to demonstrate your compliance. We will also help you establish a logbook system for recording all future monitoring activities.

Who Can Carry Out a Risk Assessment?

The law requires a risk assessment to be carried out by a “competent person”. This is someone with the necessary knowledge, training, and experience of water systems and Legionella control.

While a landlord of a simple domestic property may be able to carry out a basic assessment themselves, for most commercial, public, or complex residential properties, it is essential to use a qualified and accredited professional. Using an expert from a Legionella Control Association (LCA) registered company ensures the assessment is thorough, impartial, and meets the highest industry standards.

Reviewing Your Risk Assessment

A Legionella risk assessment is not a one-off task. The HSE’s ACoP L8 states that it must be reviewed “regularly” and immediately whenever there is reason to believe it is no longer valid. Triggers for a review include:

• – Changes to the water system or its use.
• – Changes to the use of the building or its occupants.
• – Monitoring checks indicating that control measures are no longer effective.
• – A case of Legionnaires’ disease being associated with the system.

While the old informal “two-yearly” rule has been removed from official guidance, many organisations still use it as a benchmark for reviewing assessments in low-risk environments.

Beyond the Risk Assessment: Total Legionella Management

The risk assessment is the foundation of your compliance, but it is just the beginning. The findings must be acted upon through a consistent programme of monitoring and maintenance. To learn more about how we can support you with a complete, ongoing compliance solution, please see our Legionella Management services page.

Frequently Asked Questions

• Do I need a “Legionella certificate”?

  No. There is no such thing as a “Legionella certificate” that is officially recognised by the HSE. The legally required document is the risk assessment report itself, which details the findings and control measures.

• How much does a professional risk assessment cost?

  The cost varies depending on the size and complexity of your property’s water systems. A simple residential property will cost significantly less than a large commercial building with complex systems like cooling towers. We provide tailored, fair quotations with no hidden surprises.

• What happens if I don’t do a risk assessment?

  Failing to comply with your legal duties can have serious consequences. Landlords and employers can be prosecuted even if there is only an exposure to risk, without anyone actually becoming ill. A thorough risk assessment is your primary evidence of due diligence.

Book Your Legionella Risk Assessment Today

Ensure your property is safe and legally compliant. Contact our expert team today to discuss your requirements and schedule a comprehensive Legionella risk assessment.

Call 0800 228 9627