Great, thanks for the answer. May I ask more precisely where you are building in 86xxx? Did the Water Management Office come up with the idea for the disposal themselves or did you have contacts there?
Near Ingolstadt.
No, the idea came from the civil engineer.
The utility connections are also done by the energy supplier in our case. We bought the multi-conduit pipe from the local building materials dealer (significantly cheaper than from the energy supplier) and we even picked it up with a Mini Cooper. The shell builder will install it.
I also find the prices reasonable. Also e.g. the flat rate for setting up the construction site. The road closure alone cost us €300.