Legionella Testing

Find out what a Legionella risk assessment is, why it's important for businesses, and how to make sure you comply with health and safety regulations. Get the answers here!

Discover the hidden dangers lurking in your water: Legionella bacteria. Uncover the two illnesses they can cause, Legionnaires’ disease and Pontiac fever.

What is a Legionella risk assessment?

Discover whether your water storage areas are harboring Legionella bacteria with a Legionella Risk Assessment. Get a detailed, dated report that is essential for demonstrating whether your property has any high-risk areas for Legionella. 

Or, find out if you’ve taken the necessary measures to reduce the risk of bacterial growth. Protect your property and your health with this comprehensive assessment.

A Legionella risk assessment survey examines the potential risks presented by engineered water systems, aiming to identify and assess the risks of exposure to these bacteria from work activities and water systems.

Are Legionella risk assessments a legal requirement?

You may have been hearing different things about the legal obligation to conduct Legionella risk assessments. Here’s the scoop: a Legionella risk assessment is not currently a legal requirement in the UK. 

However, the Health and Safety Executive (HSE) strongly encourages all businesses to conduct a risk assessment just to be safe. Our team of experts at Focus 360 Energy is here to answer any questions you may have about risk assessments.

When should you test for Legionella and how often?

Don’t take chances with Legionnaires’ disease. Test for Legionella if you’ve experienced a confirmed case of the disease, two or more pneumonia cases within four weeks, or received complaints about water quality or respiratory problems.

Ensuring safety is an ongoing process, not a one-time task. As per the HSE’s ACoP L8 guidelines, risk assessments should be regularly reviewed to maintain validity. Here are a few situations that may necessitate a review:

  • Alterations in the water system or its usage.
  • Changes in the building’s usage where the water system is installed.
  • Availability of new information regarding risks or control measures.
  • Indications that previously implemented control measures might no longer be effective.
  • Changes in key personnel.
  • Instances of legionnaires’ disease/legionellosis associated with the system.

Stay proactive in keeping your assessment up-to-date.

What to expect from a Legionella risk assessment?

When it comes to Legionella risk assessments, the goal is clear – help you pinpoint potential hazards and guide you towards effective remedies.

To make the process even more helpful, many building managers find it beneficial to include a traffic-light system. Imagine a red light indicating urgent actions, amber light signaling prompt action within a specified timeframe, and a green light highlighting non-urgent measures for process improvement.

Where does the growth of Legionella bacteria thrive?

Legionella thrives in temperatures between 20-45°C (77°F–113°F) and loves places with a ready supply of nutrients such as sludge, organic matter, algae, scale, and rust. Not to mention, bio-film on water surfaces is also a favorite spot for Legionella to grow. 

To make matters worse, poor water management practices and a lack of training and awareness programs are also major contributors to Legionella’s growth. Stagnant water; Changes in water quality in the municipality; Fluctuations in water temperature; Buildup of Sediments and Scale; Fluctuations in pH levels; Insufficient disinfectant; and Construction activities all are considered external factors in helping Legionella bacteria grow.

Who needs a Legionella risk assessment and who is at risk for Legionnaires’ disease?

Ensuring a Legionella risk assessment is conducted for your rental property is critical, as the unfortunate ramifications of not conducting this evaluation are severe. Especially after any water system maintenance, failure to undertake such measures holds many risks. 

Being legally responsible for incidents of Legionnaires’ disease contracted on your property is not something you want to experience. Invest in a professional assessment to alleviate worries and ensure your tenants’ safety. 

If you’re a homeowner or business owner with a swimming pool, hot tub, sauna, or steam room on your property, conducting a Legionella risk assessment is a smart move

This becomes even more vital if there are high-risk individuals, including heavy smokers, diabetics, or people with weak immunity or respiratory illnesses, exposed to the area.

How much flushing is required to prevent Legionella bacteria growth in taps?

It’s essential to flush your taps for at least two minutes to eliminate any harmful Legionella bacteria in your water. Particularly after holidays, when warm, stagnant water can foster their growth.

Need help? Seek the guidance of our experts at Focus 360 Energy to keep your property free of Legionella contamination.

How to remove Legionella risks

In certain cases, eliminating Legionella risks is better than just reducing them. For example, if you’re installing a new bathroom suite and have moved a sink and added new taps, it might result in some parts of the hot and cold water pipes becoming unnecessary. 

This stagnant water doubles as a breeding ground for Legionella bacteria. Hence, removing this redundant pipework, also known as a dead leg, eliminates this risk. Furthermore, other elements like rust and scale in such pipework act as food for these bacteria, making the whole system vulnerable to colonization.

How much should I pay for a Legionella risk assessment?

Get your Legionella Risk Assessment done today. Focus 360 Energy offers affordable prices starting at £85 + VAT for small properties and £250 + VAT for large ones. We also give discounts on multiple property assessments. Don’t wait until it’s too late – safeguard your property now!

Can you self-perform your own Legionella risk assessment? 

The answer depends on the property you’re dealing with and your expertise in handling the job.

If you’re a landlord with private properties such as flats or houses, you might not need to hire someone else to do a Legionnaires’ assessment. Typically, small domestic properties occupied all year round have low-risk factors and straightforward, simple and logical water systems.

Still, a risk assessment for Legionella is essential, and you should keep a record of the assessment and any actions taken thereafter, regularly reviewing them. 

It’s crucial to re-conduct the risk assessment if anything changes in the property that affects the risk level. For instance, if you install a new boiler, you’ll need to repeat the assessment.

Preventing Legionella bacteria: risk factors & how to stay safe

Legionella bacteria can be found in water tanks, showerheads, and spas—areas vulnerable to pneumonia-like infections if airborne. Landlords must reduce risks to vulnerable tenants, with 308 cases reported in 2019.

The Health and Safety Executive demands an evaluation of hazards, outlining legal requirements for responsible individuals. Domestic premises are low risk and minor hazards must be noted down. All landlords should take a Legionella awareness course to learn how to conduct efficient risk assessments.

Determine the dangers

The first step in a Legionella risk assessment is identifying potential sources of danger on the site. Create a list of the property’s water systems and pinpoint which ones may pose a Legionella risk. According to HSE guidelines, a thorough assessment should investigate the following:

  • Stored or recirculated water
  • Water temperature ranging from 20 to 45°C in some or all parts of the system
  • Presence of nutrient sources, such as rust, sludge, scale, and organic materials
  • Favorable conditions for bacterial growth
  • Possibility of water droplets spreading over a large area

You can spot potential risk factors by examining the property’s schematic design or visually inspecting the systems. As a landlord, you can utilize the Brightchecker system to complete and document your Legionella assessment duties with ease.

Consider who may be at risk

When it comes to suspected Legionella bacteria in your property, knowing who’s at risk is essential. Landlords must take into account factors like age, health, and smoking habits to create a comprehensive list. 

Don’t forget about employees, contractors, residents, and visitors, either – everyone needs to be considered. By carefully documenting this list, you can show that you’ve thought about everyone’s safety and taken steps accordingly.

Conducting a Legionella risk assessment

The process of conducting a Legionella risk assessment typically involves the following steps:

Step 1: Identify potential sources of Legionella contamination

Begin by conducting a thorough inspection of your building’s water systems to identify potential sources of Legionella contamination. This may include:

  • Cooling towers and evaporative condensers
  • Hot and cold water storage tanks
  • Pipework and distribution systems
  • Showers, taps, and other water outlets
  • Air conditioning systems with humidification or water spray features

Pay particular attention to areas where water may stagnate or where temperatures are conducive to Legionella growth (typically between 20°C and 45°C).

Step 2: Evaluate existing control measures and procedures

Next, evaluate the effectiveness of the existing control measures and procedures in place to minimize the risk of Legionella contamination. This may include assessing the following:

  • Water temperature controls, such as thermostats and mixing valves
  • Water treatment and disinfection processes, including the use of biocides and anti-scaling agents
  • System maintenance and cleaning procedures, including flushing and descaling of pipework and water outlets
  • Monitoring and record-keeping practices, such as temperature checks and water testing

It is essential to ensure that all control measures and procedures are properly implemented, regularly reviewed, and updated as necessary.

Step 3: Assess the vulnerability of occupants

Consider the vulnerability of the occupants in your building, particularly those who may be at higher risk of contracting Legionnaires’ disease, such as the elderly, individuals with weakened immune systems, or those with pre-existing respiratory conditions. 

Assess the adequacy of existing control measures and procedures for protecting these vulnerable individuals and consider whether any additional precautions are necessary.

Step 4: Develop and implement a Legionella control plan

Based on the findings of your Legionella risk assessment, develop a comprehensive Legionella control plan to address any identified risks or deficiencies in your existing control measures and procedures. This may include:

  • Adjusting water temperature controls to maintain temperatures outside the optimal range for Legionella growth
  • Implementing more effective water treatment and disinfection processes
  • Improving system maintenance and cleaning procedures, such as increasing the frequency of flushing and descaling
  • Enhancing monitoring and record-keeping practices to ensure ongoing compliance with water safety standards

Regularly review and update your Legionella control plan to ensure it remains effective in minimizing the risk of Legionella contamination.

Step 5: Train and educate staff

Staff responsible for maintaining and operating your building’s water systems must be properly trained and educated about the risks associated with Legionella and the importance of implementing effective control measures. 

Provide regular training sessions and resources to help staff understand their responsibilities and ensure they are equipped to carry out their duties effectively.

Documenting your Legionella risk assessment

It is essential to thoroughly document your Legionella risk assessment, including the findings, recommendations, and actions taken to address identified risks and deficiencies. 

This documentation serves as a valuable record for demonstrating compliance with water safety regulations and can be useful in the event of an insurance claim or legal dispute.

Ensure that your Legionella risk assessment documentation is readily accessible and regularly reviewed and updated to reflect any changes in your building or its occupancy.


Conducting a Legionella risk assessment is a critical component of ensuring the safety of your building and its occupants. 

By systematically identifying potential sources of Legionella contamination, evaluating existing control measures and procedures, and implementing a comprehensive Legionella control plan, you can minimize the risk of Legionnaires’ disease and ensure the well-being of those who live or work in your building. 

Regularly reviewing and updating your Legionella risk assessment will help maintain a safe environment and protect the health of your building’s occupants.

Frequently Asked Questions (FAQs) on Legionella Risk Assessments

1. What is a Legionella risk assessment?

A Legionella risk assessment thoroughly examines your water systems to determine if they could harbour Legionella bacteria. This assessment helps identify potential high-risk areas and whether proper measures have been taken to reduce bacterial growth. The goal is to protect both the property and the health of its occupants.

2. Are Legionella risk assessments legally required?

While conducting a Legionella risk assessment is not legally mandated in the UK, the Health and Safety Executive (HSE) strongly recommends it for all businesses. This practice ensures safety and compliance with health regulations, even though the law does not explicitly require it.

3. When should you test for Legionella, and how often?

Testing for Legionella is crucial under certain conditions: following a confirmed case of Legionnaires’ disease, detecting multiple pneumonia cases within a short period, or after complaints about water quality or respiratory issues. Regular reviews and risk assessment updates are recommended, especially after any changes to the water system or building usage.

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

During a Legionella risk assessment, expect a detailed report identifying potential hazards and recommending effective remediation strategies. Many assessments use a traffic-light system to prioritise actions, with red indicating urgent, amber for necessary within a set timeframe, and green for non-urgent improvements.

5. Who needs a Legionella risk assessment, and who is at risk for Legionnaires’ disease?

Landlords, business owners with facilities like pools or spas, and managers of buildings with complex water systems should conduct a Legionella risk assessment. High-risk individuals include older adults, smokers, diabetics, and those with weakened immune systems or respiratory conditions. These groups are more susceptible to Legionnaires’ disease and should be protected through proactive assessments and interventions.

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Post written by: Sam Guest

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