WISY Filtering Principle

Automatic Dirt Removal
The Secret:
  • The filter meshes inside WISY’s filters are vertical.
  • Solids such as leaves, moss or materials from production processes are simply flushed past the filter and washed away.
  • Thanks to this simple design, the filter screen has a long service life and requires very little maintenance.
  • This is a crucial advantage over any type of filter with rather horizontal filter surface. They become clogged very quickly and require frequent cleaning.
It Sounds Unbelievable, But Is Very Simple
Principal of WISY-Filters

Leaves or particles can not clog the filter

When water falls through a vertical tube, it tends to cling to the inner surface of the tube. This behavior is caused by adhesion forces which can be exploited to alter the direction of water flow. Solids do not behave in this way, they just fall straight down. Furthermore, they are captured by the fine stainless-steel mesh of the filter. Only clean water can pass into the storage tank or back to the production process.


The cross-sectional area of the connected tubing does not change at any point inside the filter housing so that larger debris particles can pass straight through. Even a tennis ball washed off the roof cannot block the rainwater pipe.

4-Step Rainwater Harvesting System
Four Easy Steps To Keep Your Rainwater Clear For A Long Time

WISY’s 4-stage cleansing principle ensures that rainwater is clean enough to store. Users of WISY’s rainwater harvesting system are not completely dependent on public water utilities and have access to their own clean water supply during dry spells.

Step 1 

Rainwater filtered by the vortex fine filter or another WISY pre-tank-filter and the downpipe filter is not only clean, but also highly oxygen-rich. This is important because the growth of anaerobic bacteria is inhibited in oxygenated water.

Step 2

The calming inlet carefully distributes fresh water in the storage tank without resuspending sediments. The water in the storage tank stays clean.

Step 3

The top surface layer of the water is regularly flushed into the multisiphon overflow, thereby preventing the formation of a surface barrier layer and ensuring an optimum exchange of oxygen between air and water. The storage tank overflow is also protected by the backflow prevention device, the vermin guard and the odour seal.

Step 4

Clear rainwater is extracted from the cleanest part of the tank, i.e. from around 20 cm beneath the water surface. The water is sucked in through the floating suction filter.

Get Quotes for Your Project

We are ready to start your project.