In this article the legionella and water safety specialists at Water Treatment Services consider if regular flushing of little used water outlets can help to control legionella and other unwanted bacteria.
The article considers the benefits of regular flushing, how it works and why it is essential for the safety of some outlets. It explains how to identify outlets that need to be flushed, whether some need to be flushed more frequently, record keeping and the importance of staff training and competence.
Does regular water flushing control legionella?
It’s almost impossible to completely remove Legionella bacteria from a manmade water system once it’s there. However, it is straightforward enough to keep it at bay – that is, to keep the bacteria well below danger levels.
There are various techniques we can use to help minimise the presence of legionella in any hot or cold water system. One of these is a simple process known as flushing. It is important to understand what flushing means and how it can help with legionella and water safety management of any building that has a water system.
How flushing of water outlets controls legionella
The idea behind the regular flushing of water outlets is simple. Most buildings have outlets (taps, showers etc.) that are less frequently used than others. Think of a hospital or care home where some rooms are commonly used and others far less so. There may be bathrooms with showers that are in regular use, while others are only occasionally used, or even not at all.
A legionella flushing regime would identify these little used outlets (shower heads, taps, and so on) and ensure they are flushed through regularly to keep the water moving. This simple task means turning on the shower head, tap, or other outlet and leaving it to run water through for a few minutes at pre-agreed intervals. This would help to expose the plumbing and outlets to temperatures that discourage the growth of bacteria. It would also help to disrupt the formation of any biofilm inside the system. It’s also important to remember that when flushing you should always ensure you minimise any spray and drain the water away safely.
Flushing outlets after temporary shutdowns
Flushing could also be used following a temporary shutdown of a building. The most obvious example here is during the COVID-19 lockdowns. Many buildings stood empty for many weeks, even months in some cases. The water in the plumbing systems was not in use, so the issue of stagnant water, disused outlets and pipework, and lack of regular cleaning routines may have arisen in some buildings. If those buildings were reopened without first being checked, including the use of a flushing regime for all water outlets, the potential danger of legionella and other bacteria being present would be higher.
Why do little used outlets need flushing?
The UK’s Health and Safety Executive determines that a little used outlet, that’s any water outlet that is used just once a week or less qualifies for the flushing procedure. Therefore, it is important to make sure you are aware of how often each part of the water system is used.
The purpose of the flushing process is to keep the water moving and so avoid stagnation. This flushing process does not need to be constant, but it does need to be regular enough to prevent certain things from happening. Firstly, Legionella bacteria prefers and can more easily multiply in stagnant water. So, when a portion of the water system doesn’t get regular use, the water will sit in the pipework and stagnate. Secondly, these stagnant conditions also make it easier for biofilm to form inside the pipework, thereby giving the bacteria an environment in which to flourish.
By adopting a regular flushing regime, it is possible to minimise the risk of legionella colonising any part of the water system.
How to find taps, showers and other outlets that need flushing?
It makes sense that the individuals responsible for finding which water outlets need flushing may not be the same individuals as those who best understand how the water system is used. For example, in a hospital, those working in specific departments or on wards will know which outlets get regular daily use and those that do not. These people can better inform those responsible for flushing outlets, giving them the information required to identify which ones need regular attention. Similarly, if the use of a specific area changes, and in turn so does the use of specific taps or other outlets, this information can be brought to the attention of those managing the legionella control and water flushing process.
Should some outlets be flushed more often than others?
Yes, this is likely to apply in some scenarios. If we continue with our hospital example, there could be areas that are more prone to having people with health conditions that put them at greater risk of contracting Legionnaires’ disease. The outlets they are most likely to use (taps and showers) should therefore be flushed more often, reducing the risk factors still further.
Keeping records of your flushing activities
Records are an essential tool in helping you stay on top of your legionella flushing regime. We can see just how important it is to maintain a consistent regime, and keeping notes of which outlets have been flushed, when, and who performed the process is important. Not only does it act as evidence of measures taken to control legionella but it also gives you a place to record any adjustments to the programme.
The importance of legionella and water safety training
Flushing can and should only be done by those with an understanding of what is required. Proper training is essential for this. The uninformed may select the wrong outlets to flush or not perform the job properly leading to a false sense of safety.
The alternative – and a more practical route to take in some cases – is to hire an outside team to perform the flushing tasks. The duty holder, responsible person, building owner or estates manager is still ultimately responsible for the safe running of the water system. However, with experts on site to help manage and run the flushing regime, there is far less chance of anything going wrong that could risk the health of those using the building.
Specialist legionella risk management solutions
Water Treatment Services offer a range of specialist legionella and water safety management solutions to support the business owners and those responsible for the safety of water systems.
Contact us today to learn how our water safety experts can help you manage your water systems, maintain regulatory compliance and so keep people safe.
With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained technicians and engineers we can offer specialist legionella risk assessments, training, water testing and other risk management solutions throughout the UK and Internationally.
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