Requirements for ancillary apartment, wiring, meters, etc.

Hello everyone, I hope we can get some help here. We are building a single-family house with a granny flat in the basement in RLP. The granny flat will be about 45 sqm and will initially be occupied by my mother. Since we do not want strangers living with us in the long term, when my mother is no longer there, which hopefully will be a long time from now, we will offer the granny flat as a holiday apartment. Possibly our son might move in there at some point.

We will receive a flat rent from my mother, and for renting it out as a holiday apartment as well (per day or week).

The question is therefore whether we can save on separate line routing for electricity and cold/hot water including meters (also for the heat pump) as well as the expansion of the meter cabinet.

According to telephone information from the KfW, these are not requirements for the subsidy. But are there regulations, for example within building law or heating cost regulations or or or, that make all these installations necessary?

Thank you for your answers!

Best regards

Hausnr.6

There are requirements for a secondary apartment, e.g. [Warm-/Wasserzähler], bathroom and kitchen facilities, separate entrance… but no heating consumption meter [nmW]

There are requirements for a granny flat, e.g. heating/water meter, bathroom and kitchen facility, separate house entrance… but no heating consumption meter as far as I know

Can you please tell me who makes these requirements? For example, state building regulations etc.? And where I can find that. I've been searching like crazy for days...

Separate entrance, bathroom and kitchen is clear and I have found that. But nothing about the pipes and meters.

Completed residential units have and require a separate meter - where to find it, I no longer know… it is firmly anchored knowledge on my part. Take a look at the general [BauVO], maybe it is stated there.

Completed residential units have and need a separate meter - where to find it, I no longer know… it is firmly anchored knowledge on my part. Take a look in the general BauVO, maybe it is stated there.

According to the attachment, this is only required from 3 residential units onwards. Hence my question.

According to the attachment, this is only required from 3 residential units onwards. Hence my question.

According to the attachment, this is only required from 3 residential units in RP. You can see that a lot is country-specific. You didn't mention your country. You only have to provide 6 sqm of storage space ;) They are probably more expensive than the modest water meters, which cost just under a hundred :D