Possible building plot - shaft on the property

Stop it!

Hello BananaJoe

does not have to be the worst. Could be integrated into the basement.

Steven

Enough guessing. What does the seller say?

Seepage shaft with overflow?

Drain cleaning services nowadays have equipment that maps the route on a chart.

I have a strong desire to remove this thing, especially under the building. No filling in with concrete.

Enough guessing. What does the seller say?

The seller (the public sector) by the way said that he "assumes that it is a well." The thing was already on the property when the state bought it, but nobody really took a good look at it.

The question is only how reliable the statement is. The seller doesn't want to give any guarantees in that regard (or otherwise)... I'm currently trying to somehow get contact details of the previous owner so I can ask him once.

I would have a strong desire to remove this thing, especially under the building. No just filling it with concrete.

I would also tend towards that. But it’s definitely not cheap, depending on how long the channel actually is. The hint towards drain cleaning is not bad; if I don’t make progress with Steven’s tips during my next visit, I will probably approach a drain cleaning service.

somehow get hold of the previous owner's contact details

If they were allotment gardens, there was or probably still is an association for them. There are definitely people who were informed about all the buildings.
The land registry office also has historical aerial photos. You can take a look there to see what used to stand on that piece of land.

Again on this:

Enough guessing. What does the seller say?

I just got the following info: The city apparently spoke with the previous owner. He reportedly said that he also used this shaft for water usage. According to him, the shaft is about 5 m deep and reaches a clay layer at the bottom. He apparently could no longer remember the branch. However, he assumes that the shaft has overall dimensions of about 1 x 2 m.

I will take a look at it with the "mobile phone on a stick" and hope that I can recognize something there.

The land registry office also has historical aerial photos. You can check what used to stand on that patch of land.

Also a good idea, I will contact them directly (of course only by phone in times of Corona)!