Paving the terrace for a new construction of a "low-built" single-family house

I guess I am partly to blame because I signed the building application, but shouldn't the architect of our general contractor have noticed something like this? He was in contact with the city.

Theoretically yes, but the problem is the following: the real client in this case is the general contractor, and in case of doubt, they don't care how you arrange your garden afterward or if you install a pump. The property is quite flat, and by digging in, you definitely created a water collection point. Such a thing is absolutely not common. Without a basement is quite reasonable in this case, because according to the soil report it would stand right in the groundwater. Not impossible, but relatively complex and expensive.

Oh, that sounds like you have to go up two steps to get to a paved terrace... but gravel would be an alternative :)

As deep as you are, yes. Then during heavy rain the water will be pushed through the patio door. If you pave one there, you should pay extremely close attention to the slope away from the house and also excavate accordingly deep beforehand. If the pipes were not in the way, I would even suggest making the terrace permeable and intentionally placing it a bit lower. Then it can absorb water from the surroundings and let it infiltrate.

If the office’s problem is first and foremost the rainwater pipe coming from the shed, you can initially drain it over the property, then you can already dig away so that more than the moat directly in front of the window remains. After all, the carport is also drained out front over the driveway.

As far as I read the plan, it really is only the shed. Therefore, I would either drain it in front through the carport or not connect it to the sewer at all. We won't be able to properly access the cistern with our patio roof either. The current plan is to direct it into a constructed wetland.