House connection: Telekom does not want to drill through the white tank

Conclusion: Telekom does not want to carry out a gas- and watertight house entry including the sealing of the cables brought in by Telekom against the house entry – instead, this should be done by the builder.

Well, of course...

nobody wants to be liable. It is known that subsequent botched work on the basement sealing sometimes leads to problems. Water stains or blooming appear. Telekom has no interest in getting involved in the dispute about who then takes over the renovation.

It would be better to make a qualified passage right during construction, or just enter the house "above ground" afterward and leave the basement as a basement.

Correct. Telekom basically never drills a hole in the exterior wall. They simply pull their cable (or have it laid by the civil engineer who makes the trench for gas, water, electricity) through the conduit planned by the construction company for all utilities inside (in our case, it was a few KG pipes back then). The whole thing is then properly sealed at the end and the job is done. If no drilling or similar preparations have been made, the process will likely drag on forever. Because nobody wants to drill into a white tank. The construction company probably dropped the ball by not installing the proper connection preparations. How do gas, water, and electricity enter your house? Did they drill or were holes prepared for it? Maybe a picture?

Your GU together with the architect messed up. The house entry must be prepared with a sealed KG pipe before pouring the basement. Look!

The holes from left to right: Multi-service, exhaust Controlled residential ventilation, wastewater, air-water heat pump, controlled residential ventilation supply air geothermal heat exchanger (green)

With which plums are you letting your house be built? Such a core drilling is quite expensive!

The fault is not Telekom's.

What does the municipality have to do with it?

Says the construction manager

Sagt der Bauleiter

Then he should show you where the municipality explicitly prohibits it (never heard of that).

As already mentioned: Telekom is not frost-sensitive and requires a very small cross-section (just one cable..). I would go into the house above the ground slab and thus avoid many problems.

Inside the house, there is surely a cable duct leading from the ground floor to the basement, if the connection socket is to be installed there. It would also be possible to install it directly in the hallway, so that the Wi-Fi router is placed in the hallway as well, saving an extra access point. Of course, this depends on how extensively the Cat7 star wiring is used; you usually don’t want something like that in the hallway.