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Legionella Risk Assessment London: Everything you need to know.

If you own a business or property in London, you must ensure that you have a legionella risk assessment carried out regularly. Legionella is a type of bacteria that can cause Legionnaires’ disease, which is a potentially fatal form of pneumonia. In this blog post, we’ll look at why legionella risk assessments are so critical and how often you need to have them carried out.

What Is Legionnaires’ Disease?

Before we go any further, it’s essential to understand what Legionnaires’ disease is and how it’s caused. Legionnaires’ disease is a form of pneumonia that can sometimes be fatal. It’s caused by the legionella bacteria, which is found in water droplets, such as those produced by showers, taps, hot tubs, and heating systems.

When people inhale aerosolized droplets containing Legionellae, they become infected. The bacteria multiply inside the cells lining the lungs, causing pneumonia. Symptoms include fever, chills, muscle aches, headaches, cough, and shortness of breath. Sometimes, it can also lead to vomiting, diarrhoea, and confusion. Most people recover after two weeks, but some people develop severe complications such as kidney failure or even death. If you experience any of these symptoms, you should seek medical help immediately.

Why Are Legionella Risk Assessments Important?

Legionella risk assessments are critical because they identify any potential sources of legionella bacteria in your property or workplace. Once these sources have been identified, they can be removed or treated to minimise the risk of exposure to the bacteria.

How Often Should I Have A Legionella Risk Assessment?

The frequency of your legionella risk assessments will depend on several factors, such as the size of your property or workplace and the number of people who work or live there. However, as a general rule of thumb, you should have a risk assessment carried out at least once a year.


Legionella Risk Assessment London: FAQs

1. Where can Legionella bacteria grow?

Legionella bacteria can be found in freshwater bodies such as lakes, reservoirs, rivers, and streams. They can, however, be found in man-made water systems such as hot and cold water systems, cooling towers, and spas.

Any natural or man-made water system, given the right combination of environmental conditions, has the potential to become a breeding ground for Legionella growth.

Legionella bacteria pose significant health risks in areas where water is stored or recirculated and where breathable water droplets may be spread in the form of aerosols.

2. What factors encourage the growth of Legionella bacteria?

Temperatures of 20-45°C (77-113°F)

Locations ready to supply nutrients (sludge, organic matter, algae, scale, rust, etc.)

Surface biofilm on water

Poor water management and a lack of training and awareness programmes.

3. What external factors can promote the growth of Legionella bacteria?

Stagnation of water

The temperature of the water

Fluctuations in municipal water quality Fluctuations in water temperature

pH variations in scale and sediment

Inadequate disinfectant levels in construction

4. When should a Legionella Risk Assessment (LRA) be performed?

If you are a building manager, landlord, or employer, it is critical that you understand the Legionella health risks and conduct a Legionella risk assessment.

The old "industry standard" recommended a Legionella risk assessment at least every two years. On the other hand, the Approved Code of Practice L8 (ACoP L8) recommends that arrangements be made to review the LRA "when there is reason to suspect it is no longer valid" so that the assessment is always up to date.

This is especially important when building occupants are classified as high-risk (the elderly, for example), as an assessment may need to be performed more frequently.

It is critical to conduct an LRA whenever there is a change:

A change in the use of the building that houses the specific water system

A change in the water system itself A change in key personnel within the company A shift from unoccupied to occupied

A revision to relevant legislation

When a case of Legionnaires' disease has been reported

5. What is the Legionella risk assessment process?

A Legionella Risk Assessment will include a review of your current records and previous assessments to ensure that all remedial work or maintenance recommendations have been followed.

A Legionella risk assessment should consist of two steps. A physical inspection and consultation with everyone involved in bacterial control, including verifying management procedures and paperwork, should occur.

The first part of the Legionella risk assessment will include a review of your current records and previous assessments to ensure that all remedial work or maintenance recommendations have been followed.

The second part of the assessment will include a tour of the site, with a particular emphasis on areas where water is stored or where aerosols may be produced.

Based on these findings, a report will be prepared, including any recommendations for actions that should be taken to reduce or eliminate the Legionella risk.

6. What should you expect from a Legionella risk assessment?

An LRA's goal is to assist you in identifying real risks and advising you on how to address any issues that arise.

Many building managers believe that including a traffic-light system in an LRA is beneficial because it helps prioritise your tasks: A red light may indicate high-priority actions that must be completed quickly. An amber light could indicate that immediate action is required within a specified time frame. A green light may indicate non-urgent actions that will aid in the improvement of your processes.

Choosing the right partner to help keep your building safe is critical. A water hygiene company that is part of a larger group can provide you with reassurance and a wide range of experience. It is critical to hire external contractors with the necessary experience and credentials.

They should, for example, be a member of professional organisations like the Legionella Control Association and the Institution of Occupational Safety and Health and have a Health and Safety Accreditation. This ensures that your company's risk assessment and Legionella control procedures are efficient and compliant.

7. Is it a legal requirement to have a Legionella risk assessment?

All employers, landlords, and premises managers are responsible for understanding and managing Legionella risk in the workplace and ensuring that a Legionella risk assessment (LRA) of all water systems is performed regularly.

Many operators prefer to delegate the task of conducting Legionella risk assessments to a third party. However, the ultimate responsibility for compliance rests with the water system's owner or operator, so it is critical to ensure that this critical work is carried out by a suitably competent water hygiene specialist who can demonstrate compliance with all relevant codes of conduct.


As you can see, legionella risk assessments are extremely important if you own a business or property in London. If you haven’t had one done recently, we recommend booking an assessment as soon as possible. And remember – if you do start to experience any symptoms of Legionnaires’ disease, seek medical help immediately.

Stay safe and compliant. Call Metro-PAT 247 Limited on 020 3600 9964 or order online.

Legionella Risk Assessment London

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