For landlords and other building or business owners who are responsible for managing hot and cold water systems in any of a broad range of residential and commercial premises, it is crucial to be alert to the risks of legionella bacteria, and the associated Legionnaires’ disease that can develop as a result from contact with these bacteria.

But what do you know about the essentials of testing for legionella in bacteria at your own property? Taking the right steps here will greatly help you to protect the users of your buildings from developing what is an uncommon, but nonetheless potentially very serious disease – so, let’s take you through those measures.

test for legionella

What is legionella?

Legionella is the name given to certain bacteria that are often present in water. The bacteria can be found in natural environments such as ponds, lakes, and rivers, as well as in manmade water systems in buildings.

As long as the necessary nutrients are available and water temperatures are between 20 degrees C and 45 degrees C, there could be a risk of legionella being present.

These lower and upper water temperatures are crucial, as legionella bacteria become dormant in conditions of below 20 degrees C, and they begin to die when temperatures exceed 50 degrees C. They don’t survive at all above about 60 degrees C.

As aforementioned, legionella is also notorious as the cause of Legionnaires’ disease. This is a lung infection that can occur in people who inhale droplets of water – from sources such as air conditioning or hot tubs – that happen to contain legionella bacteria.

How does Legionnaires’ disease spread?

Not unlike COVID-19, sufferers of Legionnaires’ disease usually become infected by breathing in airborne water droplets that contain the legionella bacteria. The condition does differ from COVID-19, though, in that it is not spread from person to person.

It is important to note that the disease can be caught in both residential and commercial buildings such as offices; the key factor is whether the legionella bacteria have got into the water supply.

What are the best conditions for legionella to grow?

As aforementioned, the legionella bacteria favour temperatures of between 20 degrees C and 45 degrees C. The likelihood of the bacteria growing also depends on what nutrients may be available in the pipes and water systems where legionella can multiply – think the likes of sediment, algae, biofilm, scale, and rust.

Areas of stagnant water with biofilm on the surface can also lend themselves to the growth of the bacteria, especially when nothing is done to address or prevent such conditions from arising.

How to prevent legionella as a landlord or business owner

As a landlord, business owner or someone else with a duty to ensure the safety of those using your buildings, you should be taking proactive steps to help guard against the risks arising from legionella. Adopting the below measures will help you meet your responsibilities.

Carry out a legionella risk assessment

A legionella risk assessment involves a technical evaluation being carried out on the given property – encompassing both physical and administrative elements – to ascertain the risk of legionella that the premises currently present, along with the steps that will be needed to ensure compliance and safety.

Whether one undertakes a legionella risk assessment at a domestic or business building, the principles of this process are broadly the same, with careful attention being paid to the hot and cold-water systems, water tanks, water heaters, and water temperature.

It is generally advisable to arrange for a skilled professional to undertake a legionella risk assessment of your building, instead of trying to take on this responsibility yourself if you lack the necessary expertise.

Check water temperatures in taps and water tanks

As we touched on above, water temperatures are a vital consideration when it comes to guarding against legionella risk in a property; above or below certain temperatures, the bacteria will not pose the risk that it would otherwise do.

You can check the water temperatures from your premises’ hot-water taps by holding an accurate thermometer in the hot-water flow for a minute, and recording the temperature on the thermometer. After that minute, the temperature should have reached at least 50 degrees Celsius. If the temperature is below this, action will be needed to remedy the issue.

The process for ascertaining the water temperatures from cold-water taps is similar; you spend two minutes holding the thermometer in the cold-water flow, and record the temperature after that time. The temperature reading should be no more than 20 degrees Celsius, and in the event of the reading being higher than this, suitable action will be required to address it.

The periodic checking of the property’s hot water storage cylinders and cold water tank temperatures will further help ensure every possible step is being taken to identify and minimise legionella risks on the premises.

Carry out a test for legionella in the water

A legionella water test involves the use of a sterilised bottle (with sodium thiosulphate) to collect a water sample, with this sample then being sent to a UKAS (United Kingdom Accreditation Service) accredited lab for analysis.

If you arrange for this process, the lab will then provide you with the results, detailing whether legionella is or isn’t present in the sample, together with the bacterial count and even information about the legionella species that may have been identified.

Make sure the water system is regularly flushed

Given what we have already said in this article about legionella bacteria tending to thrive in stagnant water, it makes sense to take every possible step to prevent such stagnant water conditions from occurring. One such sensible step would be the routine ‘flushing’ of your water system.

This should include the ‘flushing’ of your building’s taps and/or showers – the term ‘flushing’, by the way, simply referring to the process of running them as hot as possible. Doing this once a week will help ensure there is no stagnant water or bacteria in your water system that could present a risk of anyone in the building catching Legionnaires’ disease.

Flushing both hot and cold taps in your property for five minutes at a time should help ensure the greatest possible safety against legionella.

Final Thoughts

While Legionnaires’ disease may not be a greatly common condition, the potentially grave seriousness of this disease – as well as the fact that the circumstances potentially giving rise to it are so preventable – should motivate you to do everything possible to carry out suitable tests of your premises’ water.

The task of catering to your responsibilities as far as legionella compliance is concerned doesn’t need to be overwhelming or overly complicated. Indeed, we can help you achieve such compliance by providing you with the legionella risk management software that represents just one part of our complete Vision Pro platform.

Are you ready to discover the difference that Vision Pro software could make to your operations and the fulfilment of your duties as a landlord or business owner? If so, simply call us now to speak to a member of our team and book a demo.