Requirement for admissibility of the septic tank

We will build such a 3-chamber small sewage treatment plant, I think that was the technical term (have to). I don't know if the old pits are no longer operational (I guess not if they are sealed), but if you build new, you need this 3-chamber luxury version. The thing is supposed to be emptied only once a year instead of every few weeks, as I know from before.

The construction site is in Brandenburg, a few kilometers before the Berlin border.

Yes, a buddy has that too. Lives behind every hill and railway tracks. There are actually now more than just a few houses. All with cesspools. Brandenburg, just before Berlin (KW)

It is still very common here in Franconia. In the past, all of them had cesspits, later three-chamber tanks.

Today, all have been converted to fully biological small wastewater treatment plants, either newly built or the three-chamber tanks retrofitted with the biological treatment part. After treatment, the wastewater is then either discharged into the surface water channel (if available) or very often infiltrated on the property (over a large area to achieve additional treatment through microbiology in the soil). In cases where it is discharged into the surface water channel, infiltration basins were often still built on the outskirts of the villages on the karst, where the water then slowly seeps through the soil and is further treated until it eventually disappears into the mountain.