Legionella filters explained: types, certification, and when to use them
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Legionella filters are an essential component of a safe drinking water system. They form a physical barrier against the bacterium Legionella pneumophila and protect users from contamination, especially when an exceedance has been temporarily identified.
But what types of filters are there exactly, how do you recognize an approved product, and when is it advisable to use them?
What exactly does a Legionella filter do?
A Legionella filter removes bacteria from the water as it comes out of the tap or shower. This type of filter is also called a point-of-use (PoU) filter. The membrane in the filter has pores of about 0.2 micrometers: large enough for normal water flow, but small enough to effectively block bacteria.
Legionella filters are often used when an exceedance of more than 100 CFU/L is detected, in new installations that have not yet been fully flushed, or preventively in situations where vulnerable users are present, such as healthcare institutions, hotels, or sports complexes.
The two main types of Legionella filters
There are broadly two types of Legionella filters: PoU filters and PoE filters.
Point-of-Use (PoU) filters are placed directly at the tap point, for example as a shower head with an integrated filter or as an intermediate piece for an existing shower. These filters offer direct protection without the need to modify the installation. They are widely used in temporary situations, such as after an exceedance or during maintenance work.
Point-of-Entry (PoE) or inline filters are placed in the pipe before the tap point. They protect multiple tap points simultaneously, for example within one room or wing of a building. Although the name suggests they are placed at the beginning of a pipe, they are not intended for long-term use in cases of contamination. Inline filters are primarily suitable as a temporary measure or preventive protection in sensitive locations.
Certification and quality
A reliable Legionella filter has been extensively tested for microbiological safety and conformity with applicable standards. Quality filters are validated according to international standards and possess the necessary medical or sanitary approvals.
H2O Enterprise exclusively supplies Legionella filters from recognized brands such as Aqua Free, Longus and T-Safe. These products meet the highest quality standards and are suitable for use in priority installations. We are happy to advise you on which type of filter best suits your situation.
When to use which type?
A shower or tap filter (PoU) is suitable for situations where a temporary Legionella exceedance has been detected, or when preventive protection is desired for vulnerable users. Inline or PoE filters can be used to temporarily secure multiple tap points simultaneously, but are not intended as a structural solution for long-term contamination.
By applying the right type of filter at the right time, you prevent tap points from having to be taken out of service and ensure the drinking water system remains safe to use.
Lifespan and maintenance
The lifespan of a Legionella filter is a maximum of three months. After this, the filter must always be replaced to continue guaranteeing safe operation. Factors such as water quality, temperature, and frequency of use can influence the flow, but the maximum usage period remains the same. Timely replacement is crucial to prevent blockages and performance loss.
Conclusion
Legionella filters are indispensable in situations where water safety cannot be temporarily guaranteed. Whether it's a healthcare institution, hotel, or sports complex: the right filter prevents risks and ensures that you comply with the legal obligations within the Drinking Water Decree.
See which solution best suits your installation in our Legionella filters collection, or contact us for free advice.