Moderate climate zone or tropical climate?
The roof area that can be connected for the use of rainwater depends on the local rainfall, since, for example, in the tropics, significantly different values are to be expected than in temperate climate regions.
But there are also considerable differences within a climate zone. The decisive factor is the diameter of the drainage pipes.
The architect plans the pipe diameter
When constructing a new building, the diameter of the drainage pipes is determined by the architect or designer. He takes into account the local climate conditions and the size of the connected roof area.
Determine the diameter yourself
If the rainwater filter is installed subsequently, the diameter of the existing pipes is decisive. Depending on the installation position, it can be the (almost) horizontal sewer base pipe (KG pipe) in the ground or the vertical downpipe.
At the channel base pipe
KG pipes are standardized in the DN standard to match our rainwater filters. The outer diameter of the pipes is decisive for a precisely fitting connection. It is often indicated on the pipe or can be measured with the sliding gauge.
At the downpipe
If the DN specification is not directly on the downpipe or pipe clamp, you can measure it yourself. The following article explains the easiest way to do this:
Determine downpipe diameter