Construction electricity/construction water costs are the responsibility of the builder

Yes, here one must once again say that you cannot just look at individual sentences of a ruling, but the basis of such rulings is always the contractual fundamental service. , so, what does your contract say?

To my understanding, the judgment refers to several defects that the contractor could not eliminate because no construction electricity was provided by the client (builder). Since this naturally led to a lot of trouble in a domino effect, the contractor sued.

The original poster asked for our approval / disapproval of his interpretation that he does not have to bear the costs for construction electricity / construction water and apparently dreams of a legal ruling based on "majority relations" between court judgments that read similarly or oppositely:

I understand the judgment 12 U 119/21 of the Higher Regional Court Schleswig from 31.08.2022 to mean that builders usually would not have to bear the costs for construction electricity / construction water. However, I cannot find any further rulings in this sense nor any experience reports from builders who tried to refer to this decision.

...

Yes, here one must say again that you cannot just look at individual sentences of a judgment, but that the basis of such judgments is always the contractual fundamental service.

... unfortunately he only cites the final instance judgment. As if this were not difficult enough to digest in its full text, one would actually have to investigate the first instance judgment in the same procedure. He says nothing about his contract, even though that would actually be the most interesting basis from a factual point of view. Legally, as said, a Hamburg, Bremen, Lower Saxony, or Bavarian regional court could very well assess the same matter entirely differently.

The facts here are mainly two things: construction electricity and construction water are indispensable prerequisites for fulfilling a construction contract, are subject to fluctuating conditions, and are therefore commonly regulated in the market as "to be provided by the builder." It goes without saying that giving them to the builder for free can never be an option, as these are significant cost items. And, as said, the German Construction Contract Procedures (VOB) do not include them in the otherwise popular interpretation of consumer protection as a "citizen’s right to protection from naivety of the non-merchant." In some construction contracts it might be possible that the contractor agrees to include the risk of conditions for these two items in his lump sum scope of services. However, this rather speaks against the solidity of such contractors' calculations. No general contractor, no matter how large, receives free shipping vouchers from his suppliers for these two items. Ultimately, the client, as the largest stakeholder in a single-family house construction project, always has to bear these costs.

Ultimately, the client as the biggest stakeholder of a single-family house construction project always has to pay.

Not universally correct. In our contract, the employee was responsible for the utility costs. That wasn’t even negotiated. However, the OP is not the only one who finds the ruling online and wants to rely on it.

Not generally correct.
In our contract, it stated that the contractor pays the consumption costs. That was not even negotiated.

Generally, it is correct.
Whether you pay the electricity and water directly to the supplier or the employee has included it in their offer as a flat rate – in both cases, you pay. I would like to insert a semicolon here, followed by a dash and a closing parenthesis, but I am afraid of the consequences.

Not generally correct.
In our contract, it stated that the employee pays the consumption costs. That wasn’t even negotiated.

I already said,

In some construction contracts, it may be possible that the contractor agrees to include the risk of conditions for these two items in their lump-sum scope of services. However, this rather speaks against the solidity of the calculation of such contractors. No general contractor, no matter how big, receives free freight vouchers for these two items from their suppliers. Ultimately, the client as the biggest stakeholder of a single-family house construction project always has to pay for them.

... and the last sentence by no means means that the client would receive these items separately listed, but sometimes quite the opposite.

However, the original poster is not the only one who finds the ruling on the internet and wants to rely on it.

And so far without any statement regarding his motives, and also without clarifying the questions of who he actually is in which business here (construction contract with general contractor / purchase from the building contractor).

Construction power and construction water are, so to speak, the air and blood of the construction work; nothing works without them, and their meter rents etc. continue to run even on idle days. Organizationally, both client and contractor can arrange them equally well. For water, the local supplier must be used; electricity could also be procured on the market from alternative providers, so that at least conditions can be negotiated here. In this regard, however, the contractors are neither significantly more skillful nor more motivated; framework agreements are at least not known to me as the norm. Thus, for both indispensable preliminary supplies, one is dealing with considerable and poorly predictable costs in advance. Anyone dreaming of some kind of "free beer" / in-kind discount as advertising against this background cannot have all their boards on the construction fence, and that’s hardly put any more nicely.

The hope that someone else would be found to bear the cost—whether for barely relevant items or at least their unexpected cost increases (or even that such a “Saint Florian principle” would exist in law or case law)—is as old as mankind and has just as long been inevitably disappointed.

The whole thing can be shortened if you break it down to the essentials: You pay it anyway, either directly to the municipal utilities or, with an appropriate surcharge, to the contractor.

For example, I was able to buy and pick up my multi-service house entry for 500 EUR net... the civil engineer also had it as an option in his offer, for 750 EUR net, just for delivery without installation...

The contractor will always make sure he earns something from it... even if the service is supposedly included.