Infiltration of rainwater, which method?

So rainwater is not wastewater for me. Rather, water from the house is wastewater for me and it is connected to the sewer. This sewer (manhole cover) is anyway on our property, so it goes in there anyway. So I don't see any catch channels anywhere on public paths, rainwater always flows into the gutter.

I can only tell you how it is with us. It was also explicitly pointed out several times.

Mhmmmm, I just messaged with a family who also built a few meters away from us in our new development and already live there.

I’ve attached their response.
I don’t quite get it, I think I really have to go by there again.

Sickeriglu with 3 rings? That seems to be something completely different than the one from Rewatec, right?

No calculation?
The lower water authority wrote to me that they need a calculation according to xxx 138.

The sealed area above? The lawn isn’t sealed, right? Actually only the roof?!

Maybe someone with more knowledge has an answer as to what they want to tell me ops:

Sickeriglu with 3 rings? That seems to be something completely different from the one by Rewatec or

That is probably a concrete infiltration trench (looks similar to a concrete cistern, but is open at the bottom.

Sealed surfaces are basically everything that is not grass. I have been trying to explain that all along. If you take another look at Graf's diagram, you can see all the places where infiltration occurs:

Yes exactly, and on this form I only indicated the 160 sqm because this sqm number was also on the building application/drainage application from our house construction company

People, this is really not that hard to understand. The municipality is basically only interested in what you let infiltrate from your property into the public sewer system, or want to let infiltrate. There are initially 2 possibilities: a) permitted - against an annual fee depending on the sealed surface area that is discharged into the sewer system b) prohibited If b) then everything must infiltrate on your own property. Including paved surfaces, etc. Then you should have a slope away from the public paths or direct via a collection channel to an infiltration area on the property... Regarding the calculation... You can send the lower water authority a manufacturer’s specification related to the sealed area. It should be fine if everything is well described. They know the soil and groundwater level quite well. What is supposed to happen? You can ask your geotechnical engineer/geologist about the calculation. It costs a bit...