Downpipe filters for rainwater harvesting systems

Downpipe filters and rainwater collectors are installed directly in the downpipe, where they separate the rainwater from the dirt load.

Already before the water reaches the rain barrel or the cistern, it is freed from leaves and dirt in the downpipe filter.

For this purpose, the downpipe filter is inserted directly into the downpipe and connected to the rainwater storage tank.

How the WISY downpipe filters work

While coarse leaves, foliage or similar impurities fall down the center of the downpipe, water flows down along the inner walls of the pipe. In the WISY downpipe filter, the rainwater is deflected sideways by means of adhesion force and directed to the rainwater storage tank.

The debris falls further below and is ejected there or flushed directly into the sewer. Clogging of the downpipe filter is impossible, since the inner diameter does not narrow at any point in the filter. For dirt, the downpipe filter thus simply behaves like a piece of pipe.

    • Downpipe Filter for Rainwater
    • Made of stainless steel
    • Roof areas up to 150 m² or 1,615 sq.ft.
      (temperate climate zone)
    • Vertical 0.28 mm filter element integrated
    • Effective separation of dirt particles
    • 10-year guarantee
    • Easy access to filter insert
    • Extremely low maintenance
    • High oxygen enrichment
    • For roof areas up to 200 m² or 2,153 sq.ft.
      (tropical climate: 100 m² or 1,076 sq.ft.)
    • Detached and semi-detached homes
    • Rainwater for toilet flushing, washing machine, cleaning and garden irrigation
    • Vertical water flow
    • automatic overflow
    • frost-proof
    • stainless steel
    • Rainwater for garden irrigation
    • Separates rainwater to the rainwater barrel without filtration
    • For installation in downpipes
    • 10-year guarantee
    • Extremely low maintenance
    • Automatic overflow protection for the rainwater barrel
    • Rainwater for garden irrigation
    • Standpipe with integrated rainwater filter
    • Made of stainless steel
    • For roof areas of 200 m² or 2,153 ft² (temperate climate zone)
    • Low maintenance, automatic dirt removal

Why a downpipe filter is important

Without a downspout filter, dirt particles can get into the rainwater storage tank. These are often leaves from trees, moss from the roof or dead insects. Normally, this is organic material that decomposes over time and becomes a nutrient for microorganisms.

As in a pond with too high a nutrient input, this can lead to unpleasant odors in combination with a lack of oxygen. However, coarse contamination can also clog the tap or damage a pump.

A downpipe filter protects them from all this: it removes organic matter from rainwater even before it reaches the rain barrel or rainwater storage tank.

Why choosing a WISY downpipe filter rather than a rainwater pipe flap or leaf separator?

In the past, a simple rainwater pipe flap or a leaf separator was used to collect rainwater. However, a downpipe filter is far superior to both.

We inform you about the advantages of downpipe filters compared to leaf separators or rainwater pipe flaps at WISY.

Advantages of a downpipe filter compared to rainwater pipe flap

The open rainwater pipe flap redirects the entire flow of water with all the debris and allows the rainwater to splash into the tank until it is overflowing. Only when the rainwater pipe flap is closed by hand does the flow into the rain barrel stop. If it is forgotten to open the rainwater pipe flap again after some rainwater has been withdrawn, it will remain empty during the next rain shower.

Also, the rain flap is mostly used in combination with open catchment tanks or rain barrels, which bring their own disadvantages and risks. Just in passing, the additional dirt input and the considerable danger for playing children should be mentioned here.

Benefits of a downspout filter over a leaf separator

The leaf separator can deflect very coarse debris forward, but directs the flow of water downward, even if the connected rain barrel is already full. The adhesion force of the water remains completely unused with the leaf separator and can rather even lead to the fact that unintentionally excessive water is ejected to the front instead of being directed to the rainwater storage tank.

With a downpipe filter the rain barrel does not spill over

If the rain barrel is full, the water is diverted downwards in the correctly installed downpipe filter so that the barrel does not spill over. With both the rainwater flap and the leaf separator, a full rain barrel would overflow because there is no hydraulic coupling of the water level between the water but and the downpipe filter.

Downpipe filter for every downpipe

Diameter of downpipe and downpipe filter

The diameter of the downspouts is determined by the designer so that rain falling on the roof surfaces can always run off. Like the downspouts, the downspout filter must be sized sufficiently large so that it does not become an obstacle during heavy rains.

The German standard for rainwater harvesting systems defines that there must be no narrowing at any point in the rainwater filter, as otherwise leaves can collect here and a backwater can form. This rule also applies to downpipe filters.

So that you always find the right downpipe filter, WISY offers several variants of each downpipe filter for different pipe diameters. So you will find the right model for many round downpipes, so that the downpipe filter and downpipe could not clog. Check this explanation, if you are not sure how to measure your downpipe diameter.

If you think we do not offer the right diameter for your pipe or you are using a pipe with rectangular cross section area, please drop us a note through our contact form. Maybe we can help with a special version or an adapter for the local standard in your country.

What is important when installing the downpipe filter?

To achieve optimum water yield, the downpipe end coming from the top is flared slightly outward before the downpipe filter is installed. This is easy to do even for non-professionals and is most easily done with a file.

As a result, the water coming from above continues to flow along the inner wall of the pipe when it enters the downpipe filter without jumping into the middle of the pipe.

Jetzt Beratung für Fallrohrfilter und Regenwasseranlage sichern

Sollten Sie bei der Auswahl des Fallrohrfilters unsicher sein oder Fragen zu Ihrer geplanten Regenwasseranlage haben, sind wir gerne für Sie da und unterstützen Sie bei der Auswahl.

Secure downspout filter and rainwater system consultation now

If you are unsure about your downpipe filter selection or have questions about your planned rainwater harvesting system, we are here to help you make the right choice.

As an experienced manufacturer for all components of a professional rainwater harvesting system, the selection of the appropriate downpipe filter is part of our daily business. Please feel free to contact us for further information.

Our friendly and professional staff is here to help you find the right downpipe filter for your needs. We look forward to your inquiry and to welcome you soon at WISY.