Do you have to build the same property height as the neighbors?

Hello,

we are dealing with the following question (in Brandenburg) – see also the sketch in the attachment:

We own the middle, red-marked plot B. The plot was filled with soil in such a way that it ends at the same height as the neighbor at the rear. So it has a very slight slope from front to back. The slope does not matter due to the length of the plot, in such a way that rainwater could flow to the neighboring plot at the back.

Our neighbor A to our left has already had his outdoor area done. He has leveled his plot horizontally at the same height as the street curb. Since all the plots at the back have a lower ground height, neighbor A's plot height is therefore higher than that of his neighbor behind him. For this reason, neighbor A has set curbstones himself so that the rainwater does not flow directly to the rear neighbor.

Neighbor C on the right now also wants to start with his outdoor facilities, including raising the ground level of the plot. In principle, he had planned to also level the plot horizontally from the street curb to the back like plot A and then set curbstones to the rear neighbor because of the difference in height. (Plots A and C are being done by the same landscaper).

Now the following two questions arise:

1) Are we (plot B) under any obligation to always level the plot height horizontally to the street curb (like plot A) or do we have the freedom to keep the plot with our slope and plot height so that neighbors A and C would have to ensure that their rainwater does not flow onto our plot (e.g. by curbstones)?

2) According to building regulations, we would be responsible for putting up a fence between our plot B and plot C. Can we build the fence including the slope in such a way that it is effectively parallel on our sloping plot, but due to the difference in height stands slanted/not parallel to plot C's ground?

Supplement for better understanding, the site plan with the height indications (57.xx and 58.xx) shows the respective terrain elevations according to the site plan. It can be seen that, according to the site plan, there is a slight slope from the street side to the rear properties.

Are we (property B) obligated to always align the property height horizontally with the street curb?

No.

Do we have the freedom to keep the property with our slope and property height?

Yes.

So that neighbors A and C would have to ensure that their rainwater does not flow onto our property (e.g., by means of curbstones)?

Yes.

According to building law

Brandenburg Neighbor Law (BbgNRG)

Can we build the fence including the slope so that it is actually parallel on our property with the slope, but due to the height difference stands at an angle/not parallel to property C’s ground?

Yes.

All answers are subject to extraordinary provisions in the development plan, a design statute, or other local regulations.

Thank you very much for the prompt response!

As a layperson reading along... but isn't B also obligated (even without any changes to the property) to ensure that the surface water is not drained over the "rückseitige Grundstück"?

Or does that only apply if there are changes?

Or does that only apply when changes are made?

It actually only applies if changes are made to the natural water flow.
However, this is usually regulated in the respective state water law.

Accordingly, one is only obliged to prevent drainage onto the neighboring property if one alters the existing conditions (especially topography).
In that case, the neighbor has a right to injunction according to § 1004 of the German Civil Code.