Can Point-of-Use Water Filters Control Legionella, Pseudomonas & Other Waterborne Pathogens?
This expert water safety article looks at the role of point-of-use water filters, and asks if they can be used to control the health risks from legionella, pseudomonas and other waterborne pathogens that can contaminate engineered water systems.
The article considers how these specialist water filters work to protect people from legionella and other waterborne pathogens, and where and under what circumstances they should be used.
A version of this story dealing with the use of point-of-use water filters to improve water safety first appeared in Legionella Control International’s newsletter. To get it in your inbox, sign up for free here.
Can point-of-use water filters control legionella risk?
You might already suspect the answer to that question is yes, but let’s take a more detailed look. The bigger question to answer is how these filters can help maintain water safety standards, and why you might consider installing point-of-use (POU) water filters in a specific building.
We’ll explain more about these high performance water filters here, so you can better understand their role, the scenarios that might call for them, and how they complement rather than replace other water safety control measures.
How point-of-use filtration works?
Point-of-use water filters are available for taps or showerheads, as these are where you would typically draw the water from to use it directly.
A POU water filter is designed to remove small particulates, including bacteria, from the water supply at the chosen point of use, i.e., from a tap. By adding a point-of-use filter to the tap, the water coming out of it will leave behind certain particulates inside the filter itself. This process would work for that tap or showerhead only, so if you have more than one outlet you need a filter for each.
Legionella thrives in water temperatures between 20-45 degrees Celsius
Think of a sieve with large holes in it. Anything smaller than those holes is going to drop right through into the water. The smaller the holes in the sieve, the more particles you’re going to catch and remove from the water. It’s therefore important to make sure you get the correct filter size for the intended purpose.
Can point-of-use filters deal with bacteria such as legionella and pseudomonas?
Clearly, this requires a specific filtration system to remove legionella, pseudomonas and other bacteria from the water. The filters must be far finer to catch bacteria and prevent it from contaminating the water used by whomever has turned the outlet on.
There are many different types of water filter designed for specific jobs. It is therefore vital that the water safety specialists responsible for managing and maintaining a safe and reliable water supply at the property help select the most appropriate filter or filters. In hospitals and healthcare environments this is usually the Water Safety Group, supported by the Authorising Engineer (Water).
POU filters should not replace other water safety control measures
Legionella, pseudomonas and other waterborne bacteria can colonise any man-made water system, whether it issues hot or cold water (or both). POU filters can certainly help mitigate this, removing such bacteria before it reaches the point of use, whether that is a tap or showerhead, for instance.
It’s best to think of point-of-use filters as a short-term add-on – a method for further protecting those who may use water outlets when there is concern over water quality standards.
However, it is essential that all possible measures to reduce levels of legionella and other bacteria in the water system should be taken first. It is best to think of point-of-use filters as a temporary add-on – a method for further protecting those who may use certain water outlets. This could be someone at greater risk of exposure to legionella, i.e., patients in a healthcare setting. It might also mean anyone using the water supply from an infrequently used tap or outlet.
Legionella thrives if given the chance to multiply in water between 20-45 degrees Celsius. Therefore, making sure water is stored or supplied at temperatures outside this range should be your first consideration. Specifically, the UK’s safety regulator, the Health and Safety Executive call for cold water at outlets to be below 20 degrees Celsius, and hot water be above 50 degrees Celsius (55 in hospitals and healthcare encironments).
Other measures, such as ensuring a good turn-over of water to prevent stagnation, regularly maintaining and disinfecting the water system (and in some cases testing too) should help keep the levels of bacteria at safe levels.
Short-term use of point-of-use filters
Short-term use is the preferred method for using such water filters. For example, imagine a water system where raised levels of legionella or pseudomonas bacteria have been detected in one part of it. This could be a shower head or a tap that is infrequently used. In this case, treatment of the water system is called for, yet installing point-of-use water filters as necessary could also help reduce the levels of bacteria escaping from those outlets while the treatment works are undertaken.
In essence, then, we are focusing on these water filters to further protect those who might use the water system or at least one part of it. If an outlet highlights the presence of legionella bacteria, mitigation measures could be as simple as regularly flushing it through because it is not regularly in use. However, adding a POU water filter could be seen as a ‘belt and braces’ approach to safety.
How long do POU water filters last?
Another important element to be aware of is how each filter ought to be used and for how long. For example, how often should the filter be cleaned or replaced? Installing a POU water filter is only the beginning – it will eventually become clogged with particulate matter and won’t work as effectively, or may stop working altogether. It could even make the problem worse.
Point-of-use filters typically have a life-expectancy specified by the manufacturer. Once this is reached the filter would be cleaned or replaced as required. If the water system is back under full control they may no longer be required and may be removed.
Keeping water safety records
Some small businesses are not required to keep detailed records of their water safety management plans. However, in all cases, we recommend you do keep records for your own convenience.
With POU water filters, make a note of why and when they were installed, and when they should be cleaned or replaced, as required. Since they are best used for limited periods, especially when managing raised levels of legionella and other bacteria within a water system, a note should be made of when they might be removed.
Records help support the actions taken when opting for point of use water filters, so they are not forgotten and form a useful part of the overall water safety plan.
Legionella and water safety specialists
Legionella Control International is a world-leading legionella and water safety specialist. Our teams of experts support those responsible for workplace safety.
We will help you to protect your staff, patients and others in meeting your health and safety obligations in this specialist area.
We deliver a range of specialist risk management solutions including water safety and legionella risk assessment, Authorising Engineer (Water) support, water quality analysis, regulatory compliance auditing, specialist legionella training, and other services that help keep people safe.
If you would like to speak with one of our legionella specialists about managing your water safety risk call us today on 0330 223 36 86 or contact us here …
