The text is about public spaces. I had my information from the BWB regulations. They want to impose this on private property as well. However, with a transfer shaft, everything behind the meter is in your area of responsibility and liability. In this respect, you can probably do whatever you want. However, in the event of a failure, the insurance might possibly hold it against you. And if, due to a chain of very unfortunate circumstances, sewage water were somehow sucked into the drinking water pipe on your property and this could be proven (practically impossible, I think, but who knows), you would probably be liable as well. It’s just a question of how likely that would be...