Assessment of ground conditions regarding the light court

What does the development look like specifically? Rainwater/sewage separated or combined, and at what heights - relative to the planned top edge of the finished floor - are the connections/shafts located?

If all of this is sufficiently above the backflow level, there is no objection to integrating a rainwater drain into the shaft and connecting it to the sewer.

The problem may also be solved if, for example, the basement protrudes about one meter from the surrounding terrain; then narrow windows above the ground level can be realized without vulnerable light shafts.

Please also consider: no matter how sophisticated the planning is, if the execution on site is sloppy - for example, light shafts are retrofitted with many long screws and in doing so the wall sealing is perforated - you will always have problems. As mentioned, this can be avoided by slightly raising the house.

Thank you both for your answers. That reassures me because I had assessed it similarly. The window is the weak point, so leave enough "space" for the light well to the floor, add sufficient permeable material, and connect it to the drainage. And honestly, either it works that way, or the pump wouldn't be able to do anything during a hundred-year rain anyway. Then, logically, only a waterproof light well would be an option... Thank you both! Mini

have "something like that" with a 10m² terrace. It significantly increases the value of the basement apartment. I just made sure that underneath the terrace there is another 20cm of air and then 30cm of gravel. That easily holds 5000l before it reaches the windows – where should that come from?

Thank you for the feedback again!

There is a separate system, so foul water and rainwater are separate. In addition, we have to infiltrate on the property itself, with retention cistern, block storage infiltration trench, etc., calculated according to DWA A 117 for a 5-year rainfall event. Emergency overflow is permitted.
Unfortunately, I can’t find anything about the canal heights in the development plan.

I also think this speaks against a pump/lift system. It doesn’t seem to be the intention of the municipality or planners.

I’m relieved for now and will grill the company on this. Either we get hard facts from a geologist, or if necessary, we won’t agree because of this…

Best regards! Mini