Wild flowing water - What is correct?

The following appears in the Journal for Environmental and Planning Law: So the respective neighbors could jointly create infiltration basins along their common boundary. Furthermore, I imagine that each property owner could then create a kind of "bed" around their house on their property, which would then flow into the next infiltration basin at the downhill neighboring boundary. If everyone chips in and helps each other, it might go quite quickly. The debris generated must then be distributed by the farmer on his land. That way, he also contributes something.

Thanks for this source …. Except for us, everyone already has such a basin at the boundary … we will install one afterwards … unfortunately, approximately 300,000 liters of hillside water come down per hour that no basin in the world can hold …

Maybe as a help for others here who later have the same problem and want to know the legal situation. I consulted a lawyer on the topic.

The statement was: "Your summary of § 37 WHG is basically correct. Also covered is rainwater that accumulates and flows off to lower properties. Accordingly, there must generally be no obstacles such as walls. The responsible building authority can usually regulate exceptions. For this, you should contact your municipality and address the problem. Basically, you do not have to tolerate that the downstream neighbor shifts the water problem onto your property with their wall, and you can demand the removal of the obstacle."

Does the statement apply to the water that comes from above and is channeled through your property or to the water that falls as rain on your property and flows from your property to the lower neighbor? And does this also apply to water that flows to your neighbor only because you have influenced the infiltration capacity through soil sealing and compaction?

For me, a clear mistake in the planning of the development area by the municipality. The difficulties with heavy rain and the lack of infiltration on the slope belong in the development plan. These were certainly known and a solution should have been developed and demanded before the building plots were released. Is there anything about this? Otherwise, I would actually bring the issue to the building authority and make it widely known. A joint solution should interest everyone, because I don't believe the neighbors' walls will last forever under this pressure.

Does the statement apply to the water that comes from above and is channeled through your property or to the water that falls as rain on your property and flows from your property to the lower neighbor? And does this also apply to water that only flows to your neighbor because you have affected the infiltration capacity through soil sealing and compaction?

First of all, I have not influenced anything. Except for sowing grass, the terrain on our property is in its original state. We have neither paved nor gravelled there. That runoff of one’s own rainwater on one’s own property must be managed, we already agreed on that. It is solely about the water that “flows through.”

For me, a clear mistake in the planning of the building area by the municipality. The difficulties with heavy rain and the lack of infiltration on the slope belong in the development plan. These were surely known and a solution should have been developed and required before releasing the building plots. Is anything stated about that? Otherwise, I would actually bring the issue to the building authority and make a big deal out of it. A joint solution should interest everyone, because I don’t believe the neighbors’ walls have eternal life under this pressure.

Yes, and I agree with you 100%. Everyone knew that water always stood on the meadows that were there before; the municipality should have done something. But even if this now sounds a bit selfish: I have no problem. I either build a wall towards the one above me, then he has the problem (but I am not allowed to, that’s been settled by the lawyer) or I let the one below me remove the wall again, which I will do. Then the bottoms will have the problem again and they will just have to go to the municipality or we all together. However, we are hit by several strokes of fate; I therefore cannot take on this matter. I will post again shortly what the lawyer wrote after studying the development plan.

Here are the formulations from the development plan (shortened by me): "The unpolluted rainwater runoff from roof surfaces is to be collected on the property. One cistern per property, which releases the rainwater delayed into the combined sewer system, must be constructed. The cistern must be connected to the combined sewer system. House drains must not be connected to the wastewater sewer. A separation of surface water discharge from external catchment areas from the wastewater sewer system is to be aimed for. Existing drains, if any, must be restored to be suitable for discharge again if necessary. Sealing of the ground surface is to be avoided. Parking spaces and property access roads are to be designed to be as permeable as possible." The following issues exist, which I consider problematic: The undeveloped properties have of course not yet implemented any of this. Many properties have heavily sealed surfaces (but discharge their rainfall water into infiltration shafts, which according to the development plan are of course not connected to the sewer system). So unfortunately the damage has already been done and in my opinion the water coming down the slope should actually be intercepted before it reaches the development area. Additionally, the neighbors in the hollow should not have been allowed to build basements or at least they should have taken precautions against water pressure. Installing basement doors or light wells back there is too dangerous.