With a downpipe filter, you ensure that rainwater is efficiently filtered and thus cleaned and flows into the above-ground water butt or the underground cistern. In our guide you can find out how such a rainwater filter works, what types there are and what you should pay attention to when buying one.
A downpipe filter ensures clean rainwater
Our recommendations
our recommendation
Graf Garantia rain thief per grey
52.95 EUR To the product| system | classic (rain collector) |
|---|---|
| downpipe size | DN100 |
| roof surface | 200 sqm |
| material | plastic, stainless steel |
| winter operation | Yes |
| color | Gray |
The rain thief pro from Graf Garantia filters dirt from the rainwater, automatically fills the rainwater tank and also prevents the tank from overflowing. The model also impresses with the stainless steel sieve and the high water yield of around 95 percent. Further advantages: The distance between the wall and the downpipe is only 16 millimeters and the switch from summer to winter operation is effortless. The rain collector with downpipe filter harmonises with a downpipe size of DN 100 and can handle large roof areas of up to 200 square meters. The flexible connection options are also impressive. The reviewers at Amazon are very satisfied - they describe the rain thief as easy to assemble and extremely functional. our recommendation
Powermat downpipe filter downpipe filter with leaf trap DN100 Ø110 HT/KG pipes graphite
EUR 19.90 To the product| system | leaf separator |
|---|---|
| downpipe size | DN100 |
| roof surface | n/a |
| material | plastic |
| winter operation | Yes |
| color | graphite colored |
Powermat's graphite-colored downpipe filter works according to the simple leaf separator principle. It's made entirely of UV-resistant and frost-proof polypropylene - this means the utensil can remain mounted all year round, minimizing the hassle. The reviews on Amazon allow the conclusion that this is a high-quality product that serves its purpose. The good price-performance ratio is also explicitly praised. our recommendation
3P leaf separator grey
EUR 29.90 To the product| system | leaf separator |
|---|---|
| downpipe size | DN100/DN80 |
| roof surface | n/a |
| material | plastic |
| winter operation | Yes |
| color | Gray |
Like the second-placed model in our comparison, the third recommendation - a version from 3P - also functions as a leaf separator. One of the advantages of the gray downpipe filter is that it can be used flexibly - it harmonises with the downpipe sizes DN 100 and DN 80. Thanks to the reduction piece supplied, the filter can be quickly adapted to the respective conditions. For winter operation, all you have to do is remove the guide surface and close the green cover. When reading the customer reviews on amazon.de, the impression emerges that the leaf separator "does what it is supposed to do".
Purchase Criteria
Compatibility with downpipe and roof
The downpipe filter must fit into the downpipe of your roof and be designed for the size of the latter. When making your comparison, always pay attention to the manufacturer's information on the size of the downpipe and the roof area. Practical: Some downpipe filters can be used relatively flexibly, i.e. they are suitable for a broader spectrum in terms of downpipe size, for example for a diameter of DN 80 to DN 100. Attention: If too much rainwater flows through the downpipe filter, the water yield is reduced.
system
Classic downpipe filter: A cylindrical filter screen is built into the filter body - oriented either vertically or horizontally. Due to the natural adhesive force, the rainwater flows through the sieve and then gets into the rainwater tank via a connecting piece. The dirt caught in the sieve falls down through the downpipe. It is discharged into the sewer. This type is also called rain collector or rain thief.
leaf separator: It is mainly used when a deciduous tree is in the immediate vicinity of the roof surface and a lot of leaves are falling into the downpipe. As with the classic downpipe filter, the rainwater is guided through a filter screen and drained downwards, where it flows into the rainwater storage tank. The leaf separator ejects leaves and dirt to the front.
cleaning effort
Classic downpipe filters with vertically aligned filter screens are considered to be particularly easy to care for. They are also defined as "self-cleaning" because hardly any dirt gets stuck in and on the sieve. In contrast, depending on the manufacturer, downpipe filters with horizontally aligned filter screens are more complex to look after and must therefore be cleaned more frequently. Think about how important low maintenance is to you.
material
Most downpipe filters are made entirely of plastic. There are also versions that have individual components made of zinc, copper or stainless steel. Models with a stainless steel sieve are of particularly high quality because they are robust, stable and corrosion-resistant. Downpipe filters, where not only the filter housing but also the entire interior is made of plastic, are usually the least expensive, but generally do not last as long as designs with metal or steel elements and are also not quite as functional.
winter operation
Some downpipe filters can also be used in winter. First and foremost, they must be frost-resistant. If such a filter is in winter mode, the rainwater does not flow into the rainwater cistern, but directly into the sewage system. In order to activate this mode, most models simply need to close a valve. If necessary, simply read the operating instructions of the respective manufacturer to find out more about the exact procedure.
youtubefrequently asked Questions
What is a downpipe filter and what is it for?
A downpipe filter is a pre-filter that you insert into the downpipe to remove dirt from the rainwater that flows down from the roof towards the rain barrel or cistern. Downpipe filters are suitable for using rainwater in the garden and using the water for the toilet and washing machine in the house.
How does a downpipe filter work?
The exact way it works depends on the type of downpipe filter. What all variants have in common, however, is that rainwater flows from the roof into the filter, where the built-in filter catches and/or “ejects” impurities. The water filtered and cleaned in this way flows on into the rain barrel or cistern - the filter is connected to the respective rainwater tank.
How do I clean a downpipe filter?
Take out the filter screen and spray it down with your garden hose or - in the case of more stubborn dirt - a pressure washer (€119.90). Regular cleaning ensures a constantly high water yield. With classic downpipe filters, it is sufficient to carry out the measure every few months; for other models we recommend shorter cleaning intervals.
Where is the best place to buy a downpipe filter?
Downpipe filters are usually available in all well-stocked hardware stores and garden centers. Amazon.de also offers you a large selection of models. There you will also benefit from an all-round pleasant shopping experience. Ordering is easy - and it is usually easy to return items that you are not satisfied with.
How much does a downpipe filter cost?
Pure downpipe filters without rain collectors (also called rain thieves) are available from around six euros. Most of the versions cost no more than about 20 euros. Sets with a rain collector, which is partly made of metal or steel and may also function as an overflow stop for the rain barrel, usually cost around 60 euros and more.