top of page

A Guide to Legionella Testing in the Workplace

Everyone has the right to feel safe and secure in the workplace, and for that to happen, regular tests need to be undertaken to minimise risk and ensure the wellbeing of the workforce.

One such risk is legionella, a potentially deadly disease that can arise in many modern workplaces, provided the right environmental conditions are met.

As a business owner, it’s imperative to understand the many risks associated with legionella bacteria; it’s not only a legal requirement, but it can help you better prevent it and protect your staff in the long run.

If you feel like you could do with finding out more, here is a handy guide to help you get to grips with the importance of legionella testing in the workplace.

What is Legionnaires’ Disease?

Legionnaires’ disease is a severe type of pneumonia that has the potential to cause a dangerous lung infection.

Other symptoms of the disease may include headaches, muscle pains, sudden bouts of confusion, and a high temperature.

Legionella bacteria can cause a milder reaction known as Pontiac fever, which often clears up on its own after a week, whereas legionnaires’ disease can be life-threatening.

It’s caused by the inhalation of legionella bacteria from water droplets in the air, and while the bacterium is naturally occurring in bodies of water like rivers and lakes, it can become more of an immediate health issue when it’s detected in purpose-built water systems.

These kinds of systems can include:

· Air humidifiers

· Cooling towers

· Pools

· Taps

· Showerheads

· Air conditioning units

· Ventilation systems

· Potable water sources like drinking fountains

· Hot tubs

Plenty of these systems are found in countless modern workplaces, so carrying out regular tests is a must.

Legionella testing is often carried out in places like schools, care homes, and offices, as they tend to be larger buildings with more space for the bacteria to develop and spread. Plus, testing is extremely important in situations where vulnerable people may be exposed to the disease, such as in hospitals and nursing homes.

While legionnaires’ disease is uncommon in the UK, it can be extremely severe and requires immediate treatment, and figures have been higher around the world. For instance, 10,000 cases were reported in the United States in 2018, according to the Centres for Disease Control and Prevention

The Centres for Disease Control also state that about one in ten people who fall ill with legionnaires’ disease will die.

Does My Business Need a Legionella Risk Assessment?

Legally, your business must undergo a legionella assessment in the UK, the responsibility of which falls on the business owner.

The assessment consists of surveying your various water systems in order to detect legionella, and this means looking at areas in which the bacteria are known to thrive.

After potential hazards are identified, e.g., a water source containing rust, your water system will be tested, and the findings will be recorded for you to refer back to at a later date. Keeping accurate and updated records is critical when taking a pre-emptive approach to your health and safety.

Test methods consist of isolating a water sample in an effort to search for the presence of legionella bacteria. The sample will then be sent for laboratories testing, and your water system will be disinfected with chemicals.

48 hours is often enough to rid your system of the harmful bacteria, but this can vary based on the size of your premises, so it’s difficult to give a specific figure.

At Dakro, we recognise that every business is unique, and no job is too small or too large for us to take on. We’ll use a wide array of water treatment processes to ensure that your legionella issue is taken care of as soon as possible.

If you’re in need of an expert legionella testing service, don’t hesitate to reach out to our friendly team. The sooner we can sort it out, the better.

What Happens to the Business if Legionella is Detected?

Alongside the extreme risk to your employees’ health, you may be hit with a sizeable fine if legionella is detected.

For example, in 2018, the Tendring district council was fined £27,000 by the HSE for a legionnaires’ disease outbreak, according to the BBC.

It’s also incredibly damaging to a brand’s reputation, and it may take a long time to recover from the outbreak in a number of ways.

Suffice to say, if legionella is detected, you need to make sure you have put measures in place to minimise the effects and care for your workers.

Dakro can help you come up with a plan of action to support you and your company should your premises test positive.

If you’re worried about a case of legionnaires’ disease in your workplace, it is worth checking out the guidelines offered up by the Department of Health; you can find these on the government’s website.

How Often do we Need to get a Legionella Test Done?

The frequency of your testing will somewhat depend on the nature of your premises and the water system you have in place.

Generally speaking, it’s good to get a test done at least once a year, but if you operate a business that has a range of open water systems, like cooling towers and pools, you might need to test more frequently.

This is partly because legionella growth is particularly prevalent in the conditions offered up by the average temperature of systems like spa pools, as they maintain an elevated temperature (usually around 35 degrees Celsius).

Legionella Testing in Schools, Care Homes, Hospitals, and Dental Practices

Testing generally needs to happen more frequently in sensitive environments like schools, care homes, hospitals, and dental practices, as the presence of the bacteria may pose more of a risk to those inside these premises, and the complex nature of larger water systems may be better suited for spreading it.


Putting the safety of your employees first should be a top priority for any diligent business owner, and this means protecting your company from legionella. If you need an assessment done in the near future, Dakro is here to help.

10 views0 comments

Recent Posts

See All


bottom of page