Function of a drainage / Who owns the water?

Hello,

Today I also have a small problem for which I need an assessment from you. My question is, who is responsible for the proper discharge of drainage water during an excavation?

Background: my neighbor has placed L-shaped concrete blocks (the wrong way around) directly on the boundary and carried out an excavation. Behind that is a drainage system in a gravel bed on my property.

The drainage and the L-shaped blocks end about 2 meters before my garage at the boundary structure. We excavated about 1 meter deep on our property for the house and garage at the relevant spot (before placing the L-shaped blocks).

Since installing our retaining wall, the drainage now runs about 50 cm open on the neighbor’s property. Yes, it must at least be brought back to the correct height level.

The reason for my question: during today’s heavy rain, water massively emerged from the gravel bed (it works!), so the drainage completely drains onto my property. My neighbor has therefore built me a great retaining wall for the seepage water, and I have the whole mess on my side. Do I have to discharge it or can I formally involve my neighbor?

I now still have to connect the garage drainage, connect the drainage of my retaining wall, and will set a catch basin anyway; for that, I have already exposed the connection under the pallet.

I also want to make the corner look nicer, which means the drainage will not just hang around there, and I wanted to remove a part of the gravel bed and then actually build my dry stone wall with large-format pavers in place of the gravel bed. After seeing the water quantities today, however, I am wondering who is actually responsible for it: me, because it comes from my property, or the builder of the retaining wall.

PS: at least my (orange) drainage works.

I would go and do a site visit with the neighbor to see how they react. If you find a joint solution, everything is fine. If the neighbor is "difficult," you have to see what to do next. From your description, I understand that you are getting water from their property. Usually, there are regulations that water from your own property must either infiltrate on your own property or be directed into the sewer system. But first, take step 1 – maybe you can save yourself all further concerns.

We examined this together in the rain. It is somewhat more difficult; it is not his water. His property is 100% on the uphill side, bordered 50% with L stones to my property. The uphill side is on the left in the photos.

That water is surface runoff and groundwater that accumulates behind his property at the L stones or seeps through the L stones to the drainage. The drainage completely drains onto my property.

The areas above are fallow land, for which a development plan is currently being created.

Basically, we are both willing to compromise. However, I do not see why I should be responsible for draining all the accumulated water to such an extent and potentially washing out my dry stone wall.

Stupid situation. As hampshire already wrote, everyone is initially responsible for letting the water from their property seep away there or draining it into the sewer. In your case, that would mean you would have to approach the owners of the wasteland. Your neighbor actually has nothing to do with it if the water does not come from him.

I somewhat agree when it comes to surface water, however, I have three to four times the amount, as everything accumulates at the L stones and flows off on my property. And the groundwater (which is definitely present), that would normally flow onto his property, also ends up on mine.

Basically, he could have asked before building the drainage, then we would have gladly built a proper connection together. Now the damage is done. The new pictures are from this morning. The corner of the L stones is the property boundary

It's already great that you can talk to your neighbor. The situation is a bit tricky for you - but solvable. Do you have an infiltration system on the site or can you discharge surface water into the sewer?