How to get rid of Legionella in Building Water Systems
In this article the water safety specialists at Legionella Control International look at how to get rid of legionella in building water systems to keep the water clean and people safe from harm.
The article gives guidance on what to do, who should be responsible for managing the process, and what you can do to get rid of the risks or at least control them to within safe limits.
Can you get rid of legionella in your water?
No matter how big or small your business is, or how complex or simple your building water systems are, it is vital to make sure Legionella bacteria are not given a chance to multiply and spread – the consequences can be very serious.
While larger water systems tend to be more complex and therefore harder to maintain, even the smallest system can be compromised with legionella if the correct steps are not taken to prevent its growth.
If you are responsible for maintaining the water systems in use in your business premises, there is plenty you can do to make sure you prevent the growth of dangerous waterborne bacteria and so keep people safe from the effects of diseases such as Legionnaires’.
Where do you start your legionella control plan?
The process of getting rid of the legionella risks in your water systems should always start with a risk assessment – under UK health and safety law it is a legal requirement.
A legionella risk assessment will highlight any potential dangers and give you guidance on the steps that should be taken to reduce those risks to keep people safe.
Do you know what your water system looks like?
To give you a better appreciation of your water systems you should have a full schematic or plan of the system, with every outlet, every pipe, and every other feature it includes.
This schematic plan is a simple representation of your water systems and forms a blueprint to help you spot where the legionella risks may be higher than normal.
For example, the schematic drawing may show one or two dead legs of pipework which could lead to stagnation of the water.
It might help you identify a tap or shower head that is rarely used, these are often called little used outlets and can also lead to stagnation of the water – a situation that needs to be avoided.
Getting rid of your legionella risks
Once you’ve identified any legionella risks, steps can then be taken to minimise or even get rid of the risks associated with such problem areas.
Disused pipes should be removed if they are no longer in use, as they encourage stagnant water and the growth of biofilms that can form on surfaces inside the water system – biofilms are essentially somewhere for legionella to live and must be avoided.
Similarly, water outlets that are rarely used make it far more likely stagnant water will sit inside the system and create a problem.
To reduce the problems associated with low water flow or even stagnation, regular flushing is really important – flushing can eliminate stagnant water issues especially if it is built into the legionella control and maintenance plan.
Make sure the responsible person dealing with the legionella risks in your business is right for the job
The responsible person for legionella is an important risk management role and the appointed person should be competent and able to do the job required of them.
Competence to do the job properly requires a combination of experience and knowledge which likely requires training, along with regular refresher courses to make sure they are fully aware of their role and how to perform it.
Consider how alterations and new additions to the water system could affect legionella risk
Seeking expert advice on alterations to the water systems, new pipework or other parts of the system is important to help reduce the legionella risk factors there as well.
A review of the engineering plans before construction can help spot potential legionella issues so they can be designed out, saving you money and giving you a safer water system.
Make sure you keep water temperatures at acceptable levels
Controlling water temperatures is important as it is a great way of controlling legionella in your water systems.
As a rule of thumb, the cold water should be kept cold (below 20oC), and the hot water should be kept hot (above 50oC, 55oC in healthcare) at all outlets.
Depending on the building and its usage, water temperature control may also involve installing thermostatic mixing valves (TMVs) to ensure the water is not too hot at taps, showers etc.
A good example would be in care homes or hospitals, where some residents or patients may be at greater risk of scalding by hot water.
It is important to remember that you must ensure cold water is kept below 20 degrees Celsius.
Meanwhile, hot water storage should be maintained at 60 degrees Celsius or above.
Water coming from hot outlets should be at 50 degrees Celsius (50 in healthcare), thus ensuring the water supply is either above or below the ideal temperatures that legionella would flourish in.
Adopt a regular legionella maintenance, cleaning and disinfection programme
A good legionella maintenance, cleaning and disinfection programme should cover the entire water system, with regular treatments given to maintain the quality of the water within the system.
Disinfecting the system keeps the Legionella bacteria at minimal levels, preventing it from establishing itself and spreading throughout the system.
This treatment also helps to minimise the amount of biofilm throughout, along with getting rid of any dead legs or disused outlets as mentioned earlier.
In many cases, a water filtration system can also help reduce the chances of legionella taking hold.
Since water comes into the system from external sources, these sources could potentially carry bacteria in with them, along with debris and other elements that could encourage the growth of biofilm.
By filtering the water, many other risk factors can be removed prior to using the water in any manner.
Carry out regular water quality testing
Water quality testing, especially for legionella should be recorded as well, to provide a full record of all steps taken to maintain the system and keep it safe.
Water testing can help you make sure the legionella control measures you are using are working as they should.
By testing different points in the water system at regular intervals, you can be sure legionella is not secretly multiplying in one area, even when things look good elsewhere.
Using an external company such as Legionella Control International to conduct legionella testing on your behalf is an excellent idea.
You can be certain the tests are being conducted under the recommended conditions and at the correct intervals.
If you were to do this on your own and you did not complete the tests correctly, you may believe your water system is fine when it isn’t.
Getting rid of the risk of that is easy when you seek an expert company to handle that part of the process for you.
It also removes the risk that legionella could go unnoticed and end up making people seriously ill – something no one would want to happen.
Legionella risk management specialists
Our teams of legionella specialists support business owners and those responsible for the control of waterborne pathogens in the workplace, helping them to protect their staff and others and so meet their health and safety obligations in this specialist area.
We deliver expert legionella risk assessments, independent compliance auditing, training courses, expert witness support and other environmental risk management services that help keep people safe.
