Electricity and water supply before construction begins?

...But is there still any way to have water on the property without bothering the neighbor and without having to use the rain barrel

You can have one cubic meter of water delivered in a tank

As already explained, you can have the house connections for electricity and water outside the house or inside the house.

Advantage of the grey electricity box with meter at the property boundary: meter reading can be done without entering the property. Your presence is not necessary.

Advantage of the water connection with meter in a shaft at the property boundary: water for construction is available even without a special construction water connection. It is automatically frost-proof installed.

Connections outside the house have the advantage, by the way, that your house cannot be demolished without the connections being disconnected by the utility providers and reconnected expensively. Admittedly, this is not relevant for everyone. For us, it was an advantage because we demolished an existing building before starting new construction and were able to keep the old connections.

Connections and meters inside the house may be convenient in old age

Electricity comes to us, for example, via an overhead line. If an external meter is to be installed, you need an extra power pole for that.

For water supply during the construction phase, my neighbor chose an interesting alternative. He was planning a rainwater cistern anyway and simply had it installed in advance. A farmer friend filled it with a few cubic meters of water from a spring. In combination with a pump, there was construction water at no cost.

We pay €150 for the installation of a construction water connection and the flat-rate water usage.

Construction power connection - invoice from Bayernwerk:
Temporary connection up to 80A - €296
Additional cost for temporary connection at cable end - €263
plus VAT.

And from the electrician:
Construction power temporary setup - €273.70 gross

So I would recommend the following to you:.

A development before the start of construction only makes sense if the building permit is already available and also the architectural plans, so you know where the lines have to be laid.

If you do it beforehand without house planning and approval, it may be that everything has to be relocated again, so nothing is saved, but more is paid.

The plans / floor plans are in place, so that is less of a problem. We already have an idea of where such a box could be set up, but we also want to wait for the electrician's input. Maybe there are things to consider that we haven't thought of or perhaps don't even know about. I have an appointment with an electrician in our village next week, and I'll discuss it with him then. Let's see what comes out of it, I'll let you know.

And then we can continue to discuss.