Tank filters for new and existing rainwater storage tanks
Clean rainwater water all summer long: this is the wish of many homeowners who are considering the topic of rainwater harvesting. With a tank filter as part of the rainwater system, it can be fulfilled particularly easily. It does not matter whether the rainwater storage tank already exists or is being newly built.
Directly to the product: Cistern filter LineAr 100

Learn here at WISY how easy it is with a tank filter to collect only clean rainwater in the tank.
What does a tank filter do?
The tank filter separates dirt from rainwater and allows only clean water to enter into the cistern or rainwater tank. Water coming from the roof flows into the tank filter from one side and flushes leaves and foliage out the other side into the tank overflow. Only the filtered, clean rainwater flows downwards into the rainwater storage tank.
Why filter rainwater with a tank filter?
The WISY tank filter plays its advantages when the course of the pipe is predetermined and only a small height difference is possible between the inlet and outlet. This is mostly the case when the planning has already been completed or the filter gets installed subsequently. For the tank filter, the existing pipe run then does not have to be changed at all or only slightly.
Rainwater that is stored in a rainwater storage tank should be treated with a special filter for rainwater such as the tank filter in order to contain as few dirt particles as possible. When it comes from the roof, rainwater often brings many organic components, such as leaves, moss or insects. These should be separated with a tank filter, because otherwise they start to decompose in the rainwater tank and negatively affect the water quality.
No additional shaft for the rainwater filter
As the name suggests, the tank filter is placed directly in the rainwater tank. This eliminates the need for an additional manhole with a lid in the driveway or garden. All components of the 4-stage rainwater cleaning system including the tank filter are thus found in the tank. Specifically, the tank filter is located in or just below the dome shaft of the rainwater storage tank, that is, in the upper, tapered section of the rainwater tank or in an attached shaft extension of the tank.
How is the tank filter installed?
After rainwater flows down from the roof through downspouts, it changes the direction of flow to horizontal. This happens in regions with potential risk of frost about 80 cm below ground surface. Below ground the rainwater flows in pipes to the tank.
There the pipe is led through an opening into the dome shaft of the rainwater tank, so that it protrudes a bit into the inside. The tank filter with its sleeve is pushed onto this end of the pipe to fit. The dirt outlet of the tank filter is connected to the overflow of the cistern. From there, the discharge follows to the sewer or to an infiltration system.
The right rainwater filter for your project
If you are still unsure whether an tank filter is the right choice for your project or if you need another rainwater filter, please contact us. We are looking forward to your call, here you can find our contact details.
As an experienced manufacturer for all components of a professional rainwater harvesting system, the selection of the appropriate rainwater filter is part of our daily business. We will be happy to assist you with any questions you may have regarding your future rainwater system.
We at WISY look forward to your inquiry!
Here you can find the product: Cistern filter LineAr 100
